PSYC 2301 Chapter 12

statistics
-collection of numbers
– a “process” or a way of working with those numbers to address research questions
-researchers gather data (numerical), organizes it, and then analyzes it using various statistics tests to make inferences to answer the research questions
inferential analysis
-simply an educated statistical guess
-based on statistical framework in order to make decisions in a systematic, objective manner
-generally involves making educated guesses or inferences from samples to a population
-when inferring from a smaller group to a larger one, it is essential that the smaller group represents the larger group, and this why random sampling is a critical part of the process
estimation of parameters (principal type of statistical inference)
used to determine a single population parameter when there is no pre-established hypothesis about the value of the population characteristic
point estimation (estimation of parameters)
the sample mean is the best point estimate of the true value of mu (the weird sign that looks like U)
interval estimation (estimation of parameters)
establishing a range of possible values
confidence interval (estimation of parameters)
a range of possible values for mu rather than a single point estimate
degree of confidence (estimation of parameters)
-the researcher can say that the estimation is made with a certain degree of confidence
-more often than not, the degree of confidence is set at 95% or 99%
hypothesis testing
-is a statistical means to determine if the hypothesis is correct
-usually the researchers tests the null hypothesis of “no difference” (if statistical significance is found, then the investigator rejects the null hypothesis
-a directional hypothesis, developed when there is adequate prior information to take such a prediction, can be used and tested if deemed appropriate (obtaining statistical significance is more likely when a directional hypothesis is used)
researchers develop a hypothesis or statement about the outcome of the investigation
-hypotheses can be stated in several ways (null, alternative, directional)
hypothesis testing (six steps)
1) state the null and alternative hypothesis
2) state the level of significance
3) compute the statistic
4)determine the critical region (1 tail or 2 tails)
5)reject the null hypothesis if the test statistic falls in the critical region. do not reject if it falls in the acceptance region
6) state appropriate conclusion
level of significance
-the acceptance or rejection of a hypothesis based on __________, which corresponds to the area in the critical region
-many research efforts in health science establish the level of significance at the 5% alpha level, although it may be set at the .025, .01 or .001 levels
-rejecting the null hypothesis at the .05 level suggests that there is less than a 5% probability that the differences are caused by error or chance
critical region
-also known as critical z-score
-corresponds with the level of probability or significance
two tailed test
-each “tail” or end of the sample distribution is used
-the 5% area of rejection is split between the upper and lower tails of the curve since the null hypothesis is nondirectional
directional one tailed
-should be used when there is a directional hypothesis
-the 5% area of rejection is at either the upper end or lower end of the curve
region of rejection
if the researchers test statistic is below the critical z-score, the null hypothesis can be rejected
region of acceptance
if it is above the critical z-score, the researcher cannot reject the null hypothesis
type 1 error
-rejection of null hypothesis when it is true
-the alpha level of significance determines the probability of a type ___ error
type 2 error
-null hypothesis is accepted when it is false
-as alpha level of significance increases, the possibility of a type 1 error is reduced, but the chance of a type 2 error (beta) increases
-typically, type 1 error leads to unwarranted changes, whereas type 2 errors maintain the status quo when a change should occur
t-test
used when comparing two mean scores
two independent sample means (t-test)
-health science research workers frequently draw two samples from a population and assign them to a control group or to an experimental group.
-after the experimental group has been exposed to the treatment, the researchers may wish to compare the experimental to the control group.
-the mean is likely the most satisfactory measure for characterizing a group.
-a t-test is used to determine the probability that the difference between the means is a real difference rather than a chance difference.

-when the samples are greater than 30 subjects, the t critical values are expressed as z scores
(therefore the obtained t-value from the formula is compared with the z-distribution for acceptance or rejection of the null hypothesis.)

-When the samples are fewer than 30 in number, a t-table is used rather than the normal probability table (this is because the distribution curve is small samples are different from the normal curve)

two dependent sample means (t-test)
-the composition of one group has bearing on the composition of the other group.

The subjects may be matched on one or more characteristics, or the same subjects may be in a pretest-posttest experiment.
–>in such cases, the two groups are no longer independent, so a special t-test for dependent or correlated means is required.
–>the measure to be analyzed is the difference between the paired scores.

analysis of variance (ANOVA)
used when three or more mean scores are compared
analysis of variance (ANOVA)
-when comparing the mean of two groups, with one independent variable use the t-test.
-if 2+ groups are involved, one of the most powerful methods for comparing means is analysis of variance (ANOVA).
-if there is only one independent variable in the study the ANOVA is called a one-way ANOVA.
-in ANOVA, as in the t-test, a ratio of observed differences/error is used to test hypotheses.
(the ratio, called the F-ratio, uses the variance of group means as a measure of observed differences among groups)
within groups variance (ANOVA)
the sum of variances of each of the groups, is the denominator of the F-ratio
-represents the sampling error in the distribution
between groups variance (ANOVA)
-measures the variation among the means of the groups, is the the numerator in the F-ratio
-shows the influence of the experimental variable or treatment
total group variance (ANOVA)
equals the scores for all groups combined into one composite group
F-ratio (ANOVA; rationale for f-ratio)
-if the between-groups variance fails to be much greater than the within-groups variance, the health scientist would conclude that the difference between the means is like caused by sampling error.
-if the F-ratio is substantially greater than 1, it would appear that the difference is likely the result of the treatment.
-to determine whether the F-ratio is great enough to reject the null hypothesis (at the pre-determined level of significance), consult an F-table, which contains the critical values necessary for testing.
-the analysis of variance is the first step in the analysis of such designs.
-if a significant F-ratio is obtained, it is only known that somewhere in the data something other than chance is operating.
post hoc test (ANOVA)
-special form of t-test
-differ somewhat in their ability to produce significant results
Examples of special t-tests:
-Duncan’s multiple range tetst
-Tests by Newman-Keuls, Turkey, Bonferroni, and Scheffe
special t-test
-used when a significant F-ratio is obtained and it is known that somewhere in the data something other than chance operating
-researcher mus employ a special form of the t-test to isolate the presence, nature, and extent of influencing variable
-researchers must be able to justify the post hoc test used
two-way ANOVA
two independent variables are in the ANOVA analysis
three-way ANOVA
three independent variables are in the ANOVA analysis
multivariate ANOVA
more than three independent variables are in the ANOVA analysis
analysis of covariance (ANCOVA)
-is a unique version of ANOVA in that it determines the effect of one or more independent variables while simultaneously controlling for the effect of some other variables (called covariates).
-ANCOVA can also be of value when comparison groups can only be matched on the principal variable and not on others.
regression
-is concerned with directionality, prediction, and sometimes causation in studies.
-determine the contribution of one or more independent variables on the dependent variable (outcome).
-can also be used to predict the value of one variable over that of other variables.
simple linear regression
-refers to a study in which there is only one independent variable and one dependent variable (both are continuous), and the relationship can be illustrated in a straight line
-it is the simplest form of prediction since only one predictor variable is used
multiple linear regression
-assesses the linear relationship between two or more continuous independent variables and a single continuous dependent variable.
-used in several ways, and it is recommended that texts dealing with this statistical technique be consulted.
parametric statistics (
Assumptions made:
–>population scores are NORMALLY DISTRIBUTED about the mean
–>population variances of the groups are approximately equal

When deviations from these assumption are in the data, parametric statistics should not be used
–>nonparametric statistical tool should be selected
–>these techniques don’t make any assumptions about the population variance or shape of the data

nonparametric tests (advantages)
-they do not have the many restrictions required for parametric tests
-they are very suitable for health surveys and experiments in which outcomes are difficult to quantify
-they offer ease of computation
nonparametric tests (disadvantages)
-less efficient
-less specific
-fail to deal with all the special characteristics of a distribution
nonparametric tests (most frequently used nonpara tests)
-The Chi-Square Test
-The Mann-Whitney U-Test
-The Sign Test
-The Median Test
-The Wilcoxon Matched-Pairs Signed Rank Test
-The Kruskal-Wallis Test
-The Kendall Coefficient of Concordance
meta analysis
A systematic review that requires uniformity in identifying studies, displaying the results, and calculating a summary estimate of the overall results if appropriate.
Nine steps in conducting a good systematic review including meta-analysis.
meta analysis (limitations)
-inclusion of poorly conducted studies in the equation
-cost of conducting the study
-criteria being used for including primary sources are difficult to agree upon
-incomplete data are sometimes used because they are the only data available.
meta analysis (advantages)
-being able to identify a finding in a diverse array of similarly designed studies
-providing a systematic overview of findings in a particular area of study
-determining larger research questions
-enabling an alternative method when other methods are inappropriate
-being able to conduct methodological assessments of research designs
interaction effect
the effect of an additional independent variable.
A result from a factorial design, in which the difference in the levels of one independent variable changes, depending on the level of the other independent variable; a difference in differences
factorial design
There are two or more independent variables.
A study in which there are two or more independent variables, or factors.
In the most common factorial design, researchers cross the two independent variables; that is, they study each possible combination of the independent variables.
The process of using a factorial design to test limits is sometimes called testing for moderators. (moderator: variable that changes the relationship between two variables)
cells
A condition in an experiment; in a simple experiment, it can represent the level of one independent variable; in a factorial design it represents one of the possible combinations of two independent variables.
Ex: older people driving while using cell phones, driving while not using cell phones, and younger people driving while using cell phones, or driving while not using cell phones
participant variable
A variable whose levels are selected (i.e. measured), not manipulated. Because the levels are not manipulated, variables such as age, gender, and ethnicity are not truly ‘independent’ variables. However, when they are studied in a factorial design, researchers often call them independent variables for the sake of simplicity.
A variable such as age, gender, or ethnicity whose levels are selected (i.e., measured), not manipulated.
main effect
the overall effect of one independent variable on the dependent variable, averaging over the levels of the other independent variable. In other words, a main effect is a simple difference. In a factorial design with two independent variables, there are two main effects.
main effect = overall effect : the overall effect of one independent variable at a time.
marginal means
The arithmetic means for each level of an independent variable, averaging over levels of the other independent variable.
may or may not have statistical significance
How do you detect interactions from a graph?
If the lines are not parallel, there probably is an interaction. If the lines are parallel, there probably is no interaction.
When a study shows both a main effect and an interaction, which is likely more important to researchers?
The interaction is almost always more important.
What are two common reasons to use a factorial design?
1. Factorial designs can test limits; to test whether an independent variable effects different kinds of people, or people in different situations, the same way.
2. Factorial designs can test theories; can test generalizability of a causal variable and also test theories.
How can you detect an interaction from a table of means?
Start by computing two differences. Begin with one level of the first independent variable. Then go to the 2nd level of the first independent variable. Be sure to compute the difference in the same direction both times. If the differences are different, you can conclude there is an interaction in this factorial study.
Why might it be better to call a main effect an overall effect?
The term main effect is usually misleading, because it seems to suggest that it is the most important effect in a study. It is not. The interaction itself is the most important effect.
Independent – Groups Factorial Design
Both independent variables are studied as independent groups. If the design is a 2 x 2, there are four different groups of participants in the experiment.
Within – Groups Factorial Design
Both independent variables are manipulated as within groups. If the design is 2 x 2, there is only one group of participants, but they participate in all four combinations (or cells) of the design.
Mixed Factorial Designs
One independent variable is manipulated as independent groups and the other is manipulated as within – groups.
Each participant does both the manipulated and the control conditions of the study.
interaction
What is it called when the effect of one independent variable depends on the level of another independent variable?
treatment group
Which of the following is NOT an example of a participant variable?
the interaction
In a factorial design study, which effect is usually considered the most important effect?
independent-groups factorial design
Koordeman et al. (2011) conducted a study on the effect of alcohol commercials on alcohol consumption in a movie theater. Participants saw one of two types of beverage commercials: alcoholic or nonalcoholic. Their consumption of alcohol during the movie was then measured. Finally, they completed a questionnaire on their usual drinking habits. Koordeman et al. found that young adults who generally consume large amounts of alcohol each week were influenced to drink more alcohol when they saw alcohol commercials, whereas the alcohol consumption of young adults who generally consume small amounts of alcohol each week was not influenced by the type of commercial shown. What type of design is this?
type of commercial shown
Koordeman et al. (2011) conducted a study on the effect of alcohol commercials on alcohol consumption in a movie theater. Participants saw one of two types of beverage commercials: alcoholic or nonalcoholic. Their consumption of alcohol during the movie was then measured. Finally, they completed a questionnaire on their usual drinking habits. Koordeman et al. found that young adults who generally consume large amounts of alcohol each week were influenced to drink more alcohol when they saw alcohol commercials, whereas the alcohol consumption of young adults who generally consume small amounts of alcohol each week was not influenced by the type of commercial shown. Which of the following is a factor in this study?
amount of alcohol consumed by the young adult during the week
Koordeman et al. (2011) conducted a study on the effect of alcohol commercials on alcohol consumption in a movie theater. Participants saw one of two types of beverage commercials: alcoholic or nonalcoholic. Their consumption of alcohol during the movie was then measured. Finally, they completed a questionnaire on their usual drinking habits. Koordeman et al. found that young adults who generally consume large amounts of alcohol each week were influenced to drink more alcohol when they saw alcohol commercials, whereas the alcohol consumption of young adults who generally consume small amounts of alcohol each week was not influenced by the type of commercial shown. Which of the following is a participant variable in this study?
to test the limits of an effect and to test theories
What are the two main reasons researchers use factorial designs?
factorial
A _______ design is one in which there are two or more independent variables.
moderating
Interactions allow researchers to examine _________ variables.
Marginal means
___________ are the means for each level of an independent variable, averaging over levels of the other independent variable.
three main effects, three two-way interactions, and a three-way interaction
In a 2 x 2 x 2 factorial design, what are all the possible effects to test?
60
A researcher wants to run a 2 x 3 mixed factorial design. The first factor is within-subjects. The second factor is between-subjects. If the researcher wants 20 observations per cell, how many participants will he need in total?
3 independent variables, 24 cells
How many independent variables and how many cells are there in a 2 × 3 × 4 study?
correlation
When authors of a research article are describing just the results of a factorial study, which of these terms would you NOT expect to see?
reference to a peer-reviewed journal
Which of the following would NOT necessarily be a clue that the study described in a popular press article was a factorial design?
8??
Yan and Sengupta (2011) examined the effects of price, attractiveness, and consumer on the perceived tastiness and expensiveness of a dish of fried rice. The study was a 2 × 2 × 2 design that varied price (inexpensive or expensive), picture (attractive or unattractive), and consumer (self or classmate) in a between-subjects design. How many cells are there in this study?
The effect of the alcohol commercial on alcohol consumption depended on whether the viewer was usually a heavy drinker or a light drinker.
Koordeman et al. (2011) conducted a study on the effect of alcohol commercials on alcohol consumption in a movie theater. Participants saw one of two types of beverage commercials: alcoholic or nonalcoholic. Their consumption of alcohol during the movie was then measured. Finally, they completed a questionnaire on their usual drinking habits. Koordeman et al. found that young adults who generally consume large amounts of alcohol each week were influenced to drink more alcohol when they saw alcohol commercials, whereas the alcohol consumption of young adults who generally consume small amounts of alcohol each week was not influenced by the type of commercial shown. Which of the following can be inferred from the study?
tastiness and expensiveness
Yan and Sengupta (2011) examined the effects of price, attractiveness, and consumer on the perceived tastiness and expensiveness of a dish of fried rice. The study was a 2 × 2 × 2 design that varied price (inexpensive or expensive), picture (attractive or unattractive), and consumer (self or classmate) in a between-subjects design. What is the dependent variable?
mixed factorial design
Susan designed a study in which she had a group of younger adults (18-24 year-olds) and older adults (50-65 year-olds). She had both groups recite a poem by memory once in front of an audience of 50 people and once in a room by themselves. She counterbalanced the order of these tasks between participants. She had the participants rate their level of anxiety right before they recited the poem each time. What kind of study design is this?
2 x 2
Susan designed a study in which she had a group of younger adults (18-24 year-olds) and older adults (50-65 year-olds). She had both groups recite a poem by memory once in front of an audience of 50 people and once in a room by themselves. She counterbalanced the order of these tasks between participants. She had the participants rate their level of anxiety right before they recited the poem each time. What is the factorial notation for this design?
two parallel diagonal lines
Susan ran a study in which she had a group of younger adults (18-24 year-olds) and older adults (50-65 year-olds). She had both groups recite a poem by memory once in front of an audience of 50 people and once in a room by themselves. She counterbalanced the order of these tasks between participants. She had the participants rate their level of anxiety right before they recited the poem each time. Susan found that there was a main effect for age such that younger people reported being more anxious than older people. She found a main effect for audience size such that people were more anxious in the room with 50 people than they were in the room by themselves. She did not find an interaction in the results. If Susan were to graph her results, what would they look like?
6
Lisa is interested in how well people are able to detect whether another person is a “Cooperator”, a “Competitor”, or an “Individualist” simply by looking at a picture of the person’s face. She wants to know what kind of face can be identified most easily, and whether this varies by the race of the person in the picture. She designs a 2 x 3 within-group design where she has participants in her study look at faces from African-American and Caucasian people who are “Cooperators”, “Competitors”, or “Individualists.” The participants identify the personality of the person in each picture and Lisa keeps track of the number of pictures accurately identified for each picture type. How many cells was each participant in?
the number of pictures accurately identified
Lisa is interested in how well people are able to detect whether another person is a “Cooperator”, a “Competitor”, or an “Individualist” simply by looking at a picture of the person’s face. She wants to know what kind of face can be identified most easily, and whether this varies by the race of the person in the picture. She designs a 2 x 3 within-group design where she has participants in her study look at faces from African-American and Caucasian people who are “Cooperators”, “Competitors”, or “Individualists.” The participants try to identify the personality of the person in each picture and Lisa keeps track of the number of pictures accurately identified for each picture type. What is the dependent variable?
a two-way interaction between race and personality
Lisa is interested in how well people are able to detect whether another person is a “Cooperator”, a “Competitor”, or an “Individualist” simply by looking at a picture of the person’s face. She wants to know what kind of face can be identified most easily, and whether this varies by the race of the person in the picture. She designs a 2 x 3 within-group design where she has participants in her study look at faces from African-American and Caucasian people who are “Cooperators”, “Competitors”, or “Individualists.” The participants try to identify the personality of the person in each picture and Lisa keeps track of the number of pictures accurately identified for each picture type. Caucasian “Competitors” were identified more easily than the other two Caucasian personality types, but there was no difference in accuracy for African-American faces. What does this describe?
two main effects and one interaction
Lisa is interested in how well people are able to detect whether another person is a “Cooperator”, a “Competitor”, or an “Individualist” simply by looking at a picture of the person’s face. She wants to know what kind of face can be identified most easily, and whether this varies by the race of the person in the picture. She designs a 2 x 3 within-group design where she has participants in her study look at faces from African-American and Caucasian people who are “Cooperators”, “Competitors”, or “Individualists.” The participants try to identify the personality of the person in each picture and Lisa keeps track of the number of pictures accurately identified for each picture type. What are all the differences that must be examined?
What is it called when the effect of one independent variable depends on the level of another independent variable?

interaction

main effect

overall effect

mediation

a
Which of the following is NOT an example of a participant variable?

age

sex

years of education

treatment group

d
In a factorial design study, which effect is usually considered the most important effect?

the main effect of the first independent variable

the interaction

the main effect of the second independent variable

the overall effect

b
Koordeman et al. (2011) conducted a study on the effect of alcohol commercials on alcohol consumption in a movie theater. Participants saw one of two types of beverage commercials: alcoholic or nonalcoholic. Their consumption of alcohol during the movie was then measured. Finally, they completed a questionnaire on their usual drinking habits. Koordeman et al. found that young adults who generally consume large amounts of alcohol each week were influenced to drink more alcohol when they saw alcohol commercials, whereas the alcohol consumption of young adults who generally consume small amounts of alcohol each week was not influenced by the type of commercial shown. What type of design is this?

within-groups factorial design

mixed factorial design

independent-groups factorial design

nested factorial design

c
Koordeman et al. (2011) conducted a study on the effect of alcohol commercials on alcohol consumption in a movie theater. Participants saw one of two types of beverage commercials: alcoholic or nonalcoholic. Their consumption of alcohol during the movie was then measured. Finally, they completed a questionnaire on their usual drinking habits. Koordeman et al. found that young adults who generally consume large amounts of alcohol each week were influenced to drink more alcohol when they saw alcohol commercials, whereas the alcohol consumption of young adults who generally consume small amounts of alcohol each week was not influenced by the type of commercial shown. Which of the following is a factor in this study?

type of commercial shown

amount of alcohol consumed during the movie

young adults who consume small amounts of alcohol each week

the movie shown

a
Koordeman et al. (2011) conducted a study on the effect of alcohol commercials on alcohol consumption in a movie theater. Participants saw one of two types of beverage commercials: alcoholic or nonalcoholic. Their consumption of alcohol during the movie was then measured. Finally, they completed a questionnaire on their usual drinking habits. Koordeman et al. found that young adults who generally consume large amounts of alcohol each week were influenced to drink more alcohol when they saw alcohol commercials, whereas the alcohol consumption of young adults who generally consume small amounts of alcohol each week was not influenced by the type of commercial shown. Which of the following is a participant variable in this study?

type of commercial shown

amount of alcohol consumed by the young adult during the week

amount of alcohol consumed during the movie

the movie shown

b
What are the two main reasons researchers use factorial designs?

to increase construct validity and to test theories

to increase construct validity and to increase internal validity

to test the limits of an effect and to test theories

to use fewer participants and to test the limits of an effect

c
A _______ design is one in which there are two or more independent variables.

factorial

repeated measures

concurrent measures

pretest-posttest

a
Interactions allow researchers to examine _________ variables.

mediating

moderating

confounding third

main effect

b
___________ are the means for each level of an independent variable, averaging over levels of the other independent variable.

Moderating variables

Factorial designs

Interaction effects

Marginal means

d
In a 2 x 2 x 2 factorial design, what are all the possible effects to test?

two main effects and a two-way interaction??

three main effects and three-way interaction

three main effects, three two-way interactions, and a three-way interaction

three main effects, three two-way interactions, and three three-way interactions

c
A researcher wants to run a 2 x 3 mixed factorial design. The first factor is within-subjects. The second factor is between-subjects. If the researcher wants 20 observations per cell, how many participants will he need in total?

20

40

60

120

c
How many independent variables and how many cells are there in a 2 × 3 × 4 study?

2 independent variables, 4 cells

2 independent variables, 9 cells

3 independent variables, 9 cells

3 independent variables, 24 cells

d
When authors of a research article are describing just the results of a factorial study, which of these terms would you NOT expect to see?

correlation

main effect

interaction effect

significant

a
Which of the following would NOT necessarily be a clue that the study described in a popular press article was a factorial design?

the phrase “it depends”

reference to a peer-reviewed journal

the use of a participant variable as well as another independent variable

phrasing that suggests that there was a difference in the differences

b
Yan and Sengupta (2011) examined the effects of price, attractiveness, and consumer on the perceived tastiness and expensiveness of a dish of fried rice. The study was a 2 × 2 × 2 design that varied price (inexpensive or expensive), picture (attractive or unattractive), and consumer (self or classmate) in a between-subjects design. How many cells are there in this study?

1

3??

8??

16

c
Koordeman et al. (2011) conducted a study on the effect of alcohol commercials on alcohol consumption in a movie theater. Participants saw one of two types of beverage commercials: alcoholic or nonalcoholic. Their consumption of alcohol during the movie was then measured. Finally, they completed a questionnaire on their usual drinking habits. Koordeman et al. found that young adults who generally consume large amounts of alcohol each week were influenced to drink more alcohol when they saw alcohol commercials, whereas the alcohol consumption of young adults who generally consume small amounts of alcohol each week was not influenced by the type of commercial shown. Which of the following can be inferred from the study?

The alcohol commercial increased the alcohol consumption of all viewers.

The effect of the alcohol commercial on alcohol consumption depended on whether the viewer was usually a heavy drinker or a light drinker.

The alcohol commercial had no effect on the consumption of alcohol.

The effect of the alcohol commercial on alcohol consumption was unpredictable.

b
Yan and Sengupta (2011) examined the effects of price, attractiveness, and consumer on the perceived tastiness and expensiveness of a dish of fried rice. The study was a 2 × 2 × 2 design that varied price (inexpensive or expensive), picture (attractive or unattractive), and consumer (self or classmate) in a between-subjects design. What is the dependent variable?

tastiness and expensiveness

price

picture

consumer

a
Susan designed a study in which she had a group of younger adults (18-24 year-olds) and older adults (50-65 year-olds). She had both groups recite a poem by memory once in front of an audience of 50 people and once in a room by themselves. She counterbalanced the order of these tasks between participants. She had the participants rate their level of anxiety right before they recited the poem each time. What kind of study design is this?

independent-groups factorial design

within-groups factorial design

mixed factorial design

concurrent measures design

c
Susan designed a study in which she had a group of younger adults (18-24 year-olds) and older adults (50-65 year-olds). She had both groups recite a poem by memory once in front of an audience of 50 people and once in a room by themselves. She counterbalanced the order of these tasks between participants. She had the participants rate their level of anxiety right before they recited the poem each time. What is the factorial notation for this design?

2 x 2

1 x 2

2 x 2 x 2

2 x 4

a
Susan ran a study in which she had a group of younger adults (18-24 year-olds) and older adults (50-65 year-olds). She had both groups recite a poem by memory once in front of an audience of 50 people and once in a room by themselves. She counterbalanced the order of these tasks between participants. She had the participants rate their level of anxiety right before they recited the poem each time. Susan found that there was a main effect for age such that younger people reported being more anxious than older people. She found a main effect for audience size such that people were more anxious in the room with 50 people than they were in the room by themselves. She did not find an interaction in the results. If Susan were to graph her results, what would they look like?

two parallel horizontal lines

two parallel diagonal lines

two parallel vertical lines

two crossed lines

b
Lisa is interested in how well people are able to detect whether another person is a “Cooperator”, a “Competitor”, or an “Individualist” simply by looking at a picture of the person’s face. She wants to know what kind of face can be identified most easily, and whether this varies by the race of the person in the picture. She designs a 2 x 3 within-group design where she has participants in her study look at faces from African-American and Caucasian people who are “Cooperators”, “Competitors”, or “Individualists.” The participants identify the personality of the person in each picture and Lisa keeps track of the number of pictures accurately identified for each picture type. How many cells was each participant in?

1

2

3

6

d
Lisa is interested in how well people are able to detect whether another person is a “Cooperator”, a “Competitor”, or an “Individualist” simply by looking at a picture of the person’s face. She wants to know what kind of face can be identified most easily, and whether this varies by the race of the person in the picture. She designs a 2 x 3 within-group design where she has participants in her study look at faces from African-American and Caucasian people who are “Cooperators”, “Competitors”, or “Individualists.” The participants try to identify the personality of the person in each picture and Lisa keeps track of the number of pictures accurately identified for each picture type. What is the dependent variable?

the number of pictures accurately identified

race of the personality in the picture

personality of the person in the picture

race of the participant

a
Lisa is interested in how well people are able to detect whether another person is a “Cooperator”, a “Competitor”, or an “Individualist” simply by looking at a picture of the person’s face. She wants to know what kind of face can be identified most easily, and whether this varies by the race of the person in the picture. She designs a 2 x 3 within-group design where she has participants in her study look at faces from African-American and Caucasian people who are “Cooperators”, “Competitors”, or “Individualists.” The participants try to identify the personality of the person in each picture and Lisa keeps track of the number of pictures accurately identified for each picture type. Caucasian “Competitors” were identified more easily than the other two Caucasian personality types, but there was no difference in accuracy for African-American faces. What does this describe?

a main effect

a two-way interaction between race and personality

a two-way interaction between Caucasian and personality

a three-way interaction between race, personality, and accuracy

b
Lisa is interested in how well people are able to detect whether another person is a “Cooperator”, a “Competitor”, or an “Individualist” simply by looking at a picture of the person’s face. She wants to know what kind of face can be identified most easily, and whether this varies by the race of the person in the picture. She designs a 2 x 3 within-group design where she has participants in her study look at faces from African-American and Caucasian people who are “Cooperators”, “Competitors”, or “Individualists.” The participants try to identify the personality of the person in each picture and Lisa keeps track of the number of pictures accurately identified for each picture type. What are all the differences that must be examined?

three main effects and two interactions

two main effects and two interactions

three main effects and one interaction

two main effects and one interaction

d
Interaction
How two independent variables are related, whether one depends on the other.
– difference in differences = the effect of one independent variable on the dependent variable depends on on the level of the other independent variable
cross over interaction
when lines cross each other in demonstrating interaction (hot and cold foods/ ice cream pancakes)
Spreading interaction
– lines not parallel, do not cross over ( treat and no treat/ say something and say nothing)
– one line flat, one line increase or decrease but never cross
Factorial Designs
a design in which there are two or more independent variables (aka factors).
Crossed Factorial Design
-factorial design where researchers cross the two independent variables and study each possible combination of the independent variables.
Nested Factorial Design
One independent variable in primary, and the other indpendent variable is nested under it
i.e. researcher studies two school districts and then three schools within each district (district is first IV and three schools are second, nested, IV)
Participant Variable
Variable whose level are selected (measured) and not manipulated
i.e. age, sex, ethnicity, and culture
– not truly independent variables
Factorial Designs Can Test Limits
-test whether IV affects different kinda of people, or people in different situations, in the same way.
-would cell phone use while driving only affect one age group? or have same effect on people of different ages?
-function as form of external validity: testing whether effect generalizes (when IV effects groups in the same way. suggests effect generalizes to all)
-Interactions show moderators
– Test Theories
Results of Strayer and Dweyer’s studies
– effect of talking on a cell phone did not depend on age. Older drivers did tend to brake more slowly than younger ones, consistent with past research on aging drivers.
-the effect of using a cell phone did not differ with age = cell phone use did not interact with age.
moderator
variable that changes the relationship between two other variable.

-in factorial language moderator is an independent variable that changes the relationship between another independent variable and a dependent variable. (results in an interaction)

i.e. driver age did not moderate impact of cell phone use on brake time

Main Effect
the overall effect of one independent variable on the dependent variable, averaging over the other levels of he other independent variable
– not necessarily most important
-simple difference
Marginal Means
means for each level of an independent variable
– may or may not be statistically significant (if not- no effect)
Interaction cont.
the difference of the simple differences
-interaction is almost always more important
Independent Groups Factorial Designs
-both independent variables are manipulated as independent groups
– in a 2×2 there are four independent groups
Within-Groups Factorial Designs
– both independent variables are manipulated as within groups.
– in a 2×2 there is only one group of participants who participate in all four combinations
Mixed Factorial Designs
-one independent variable is manipulated as independent groups and the other is manipulated within groups
– i.e. old and young group, each group drove with and without cellphone condition
-strayer and and drews
Increasing number of independent variables
__ x __ x __
^ level of each dependent variable
– with each additionial variable need to test main effect ( 2x2x2) need to test for three main effects
Gucciardi and Dimmock (2008) reported on an experiment on choking under pressure in skilled golfers. They varied anxiety level and putting condition in a 2 × 3 within-group design. Anxiety level (low or high) was varied with a competition being introduced following the low-anxiety trials. The putting conditions were thinking of cue words about either putting technique, irrelevant items, or a single swing thought such as “smooth.” Mean distance from hole was computed for the 10 putts in each condition. What are all the differences that must be examined?
What are all the differences that must be examined?
-two main effects and one interaction
There are two independent variables, so there are two main effects and one interaction possible, even though one variable has three levels.

How many cells was each golfer in?
-6

After reading a report by Rockoff (2010), Yingying is studying the effects of others present and their roles on the rate of gambling bets using a simulated slot machine. Her levels of others present are one, two, or six. Her levels of roles are gamblers and observers. She constructs a 2 × 3 table of her results of average time between bets. There are two rows for the roles and three columns for the others present. The values in the first row are 10, 20, and 20 and in the second row are 20, 10, and 10. Describe her results.
main effect of role, no effect of others present, and an interaction
Yan and Sengupta (2011) examined the effects of price, attractiveness, and consumer on the perceived tastiness and expensiveness of a dish of fried rice. The study was a 2 × 2 × 2 design that varied price (inexpensive or expensive), picture (attractive or unattractive), and consumer (self or classmate) in a between-subjects design. How many cells are there in this study?
8
What are the two main reasons to use factorial designs?
to test limits and to test theories
A recent study (Koordeman et al., 2011), conducted in the Netherlands, on the effects of commercials for alcohol or alcohol consumption in the movie theater, found that young adults who consume large amounts of alcohol each week are influenced by the commercials, whereas young adults who consume small amounts of alcohol each week were not influenced. Participants saw one of two types of beverage commercials: alcoholic or nonalcoholic. Their consumption of alcohol during the movie was then measured. Finally, they completed a questionnaire on their drinking habits. What type of design is this?
-independent-groups factorial
When authors of a research article are describing just the results of a factorial study, which of these terms would you not expect to see?
“Correlation” is not a term used in describing the results of a strictly factorial study, though it may be used within the same article.
Which of the following would not be a cue that the study was a factorial design in a popular press article?
reference to a peer-reviewed journalq
A recent study (Koordeman et al., 2011), conducted in the Netherlands, on the effects of commercials for alcohol or alcohol consumption in the movie theater, found that young adults who consume large amounts of alcohol each week are influenced by the commercials, whereas young adults who consume small amounts of alcohol each week were not influenced. Participants saw one of two types of beverage commercials: alcoholic or nonalcoholic. Their consumption of alcohol during the movie was then measured. Finally, they completed a questionnaire on their drinking habits. What is a factor in this study?
type of commercial shown
To achieve a goal of 20 observations per cell in a 2 × 2 × 3 mixed experiment with the first two factors run within groups and the last factor run between groups, what would be the number of participants needed?
– 60
If this was just a 2 × 2 within-groups design, it would need just 20 participants. Adding the third between groups factor makes 60 necessary: 20 for each level.
Gucciardi and Dimmock (2008) reported on an experiment on choking under pressure in skilled golfers. They varied anxiety level and putting condition in a 2 × 3 within-group design. Anxiety level (low or high) was varied with a competition with financial compensation being introduced following the low anxiety-level performance. The putting conditions were thinking of cue words about putting technique, thinking of irrelevant cue words, and thinking about a single swing thought such as “smooth.” Mean distance from hole was computed for the 10 putts in each condition. What is the dependent variable?
mean distance from hole
In a factorial experiment, which is the most important effect?
the interaction
Yan and Sengupta (2011) examined the effects of price, attractiveness, and consumer on the perceived tastiness and expensiveness of a dish of fried rice. The study was a 2 × 2 × 2 design that varied price (inexpensive or expensive), picture (attractive or unattractive), and consumer (self or classmate) in a between-subjects design. A main effect of price and a main effect of picture were found. It was found that the picture had a greater impact on tastiness/expensiveness judgments in self than in classmate. What type of interaction does this describe?
a two-way interaction between picture and consumer
-This means that in looking at the tastiness/expensiveness ratings for self, there is a larger difference between the attractive and unattractive ratings than there is in those ratings for classmate.
What differences need to be investigated when a three-way design is used?
-three main effects, three two-way interactions, and a three-way interaction
Yan and Sengupta (2011) examined the effects of price, attractiveness, and consumer on the perceived tastiness and expensiveness of a dish of fried rice. The study was a 2 × 2 × 2 design that varied price (inexpensive or expensive), picture (attractive or unattractive), and consumer (self or classmate) in a between-subjects design. A main effect of price and a main effect of picture were found. It was found that the impact of price on tastiness/expensiveness judgments was weaker in the self than in the classmate. What type of interaction does this describe?
a two-way interaction between price and consumer
-This means that in looking at the tastiness/expensiveness ratings for self, there is a smaller difference between the inexpensive and expensive ratings than there is in those ratings for classmate.
After reading a report by Rockoff (2010), Yingying is studying the effects of others present and their roles on the rate of gambling bets using a simulated slot machine. Her levels of others present are one, two, or six. Her levels of roles are gamblers and observers. She constructs a 2 × 3 table of her results of average time between bets. There are two rows for the roles and three columns for the others present. The values in the first row are 10, 15, and 20 and in the second row are 20, 15, and 10. Describe her results.
no effect of role, no effect of others present, and an interaction
-The marginal means are the same for both factors and there are differences in the differences in each column.
Yan and Sengupta (2011) examined the effects of price, attractiveness, and consumer on the perceived tastiness and expensiveness of a dish of fried rice. The study was a 2 × 2 × 2 design that varied price (inexpensive or expensive), picture (attractive or unattractive), and consumer (self or classmate) in a between-subjects design. What is the dependent variable?
tastiness and expensiveness
How many independent variables and how many cells are there in a 2 × 3 × 4 study?
3 independent variables, 24 cells
A recent study (Koordeman et al., 2011), conducted in the Netherlands, on the effects of commercials for alcohol or alcohol consumption in the movie theater, found that young adults who consume large amounts of alcohol each week are influenced by the commercials, whereas young adults who consume small amounts of alcohol each week were not influenced. Participants saw one of two types of beverage commercials: alcoholic or nonalcoholic. Their consumption of alcohol during the movie was then measured. Finally, they completed a questionnaire on their drinking habits. What is a participant variable in this study?
amount of alcohol consumed by the young adult during the week
-The weekly alcohol consumption of the participant was selected, not manipulated.
Yan and Sengupta (2011) examined the effects of price, attractiveness, and consumer on the perceived tastiness and expensiveness of a dish of fried rice. The study was a 2 × 2 × 2 design that varied price (inexpensive or expensive), picture (attractive or unattractive), and consumer (self or classmate) in a between-subjects design. Which variable is a participant variable?
consumer
price
picture
all of them are manipulated
What is it called when the effect of one independent variable depends on the level of the other independent variable?
interaction
Gucciardi and Dimmock (2008) reported on an experiment on choking under pressure in skilled golfers. They varied anxiety level and putting condition in a 2 × 3 within-group design. Anxiety level (low or high) was varied with a competition being introduced following the low-anxiety trials. The putting conditions were thinking of cue words about either putting technique, irrelevant items, or a single swing thought such as “smooth.” Mean distance from hole was computed for the 10 putts in each condition. High anxiety increased distance in the technique condition but not in the other two conditions. What does this describe?
a two-way interaction between anxiety and condition
-This wording suggests that the dependent variable was changed by the anxiety manipulation in the technique condition, but not in the other conditions.
After reading a report by Rockoff (2010), Yingying is studying the effects of others present and their roles on the rate of gambling bets using a simulated slot machine. Her levels of others present are one, two, or six. Her levels of roles are gamblers and observers. She constructs a 2 × 3 table of her results of average time between bets. There are two rows for the roles and three columns for the others present. The values in the first row are 15, 15, and 15 and in the second row are 20, 15, and 10. Describe her results.
no effect of role, main effect of others present, and interaction
-Increasing the Number of Levels of an Independent Variable—The marginal means differ for both factors and there are differences in the differences in each column.
Gucciardi and Dimmock (2008) reported on an experiment on choking under pressure in skilled golfers. They varied anxiety level and putting condition in a 2 × 3 within-group design. Anxiety level (low or high) was varied with a competition being introduced following the low-anxiety trials. The putting conditions were thinking of cue words about either putting technique or irrelevant items, or a single swing thought such as “smooth.” Mean distance from hole was computed for the 10 putts in each condition. The main effect for anxiety was not significant. What does this mean about the marginal means?
The marginal means for the two anxiety conditions are not significantly different.
-Marginal means are used to inspect the main effects, and in the case of a not significant main effect of anxiety, they are very close to each other.
A recent study (Koordeman et al., 2011), conducted in the Netherlands, on the effects of commercials for alcohol or alcohol consumption in the movie theater, found that young adults who consume large amounts of alcohol each week are influenced by the commercials, whereas young adults who consume small amounts of alcohol each week were not influenced. Participants saw one of two types of beverage commercials: alcoholic or nonalcoholic. Their consumption of alcohol during the movie was then measured. Finally, they completed a questionnaire on their drinking habits. What is a participant variable in this study?
amount of alcohol consumed by the young adult during the week
After reading a report by Rockoff (2010), Yingying is studying the effects of others present and their roles on the rate of gambling bets using a simulated slot machine. Her levels of others present are one, two, or six. Her levels of roles are gamblers and observers. She constructs a 2 × 3 table of her results of average time between bets. There are two rows for the roles and three columns for the others present. The values in the first row are 15, 15, and 15 and in the second row are 20, 15, and 10. Describe her results.
no effect of role, main effect of others present, and interaction
A recent study (Koordeman et al., 2011), conducted in the Netherlands, on the effects of commercials for alcohol or alcohol consumption in the movie theater, found that young adults who consume large amounts of alcohol each week are influenced by the commercials, whereas young adults who consume small amounts of alcohol each week were not influenced. Participants saw one of two types of beverage commercials: alcoholic or nonalcoholic. Their consumption of alcohol during the movie was then measured. Finally, they completed a questionnaire on their drinking habits. What is a factor in this study?
type of commercial shown
Gucciardi and Dimmock (2008) reported on an experiment on choking under pressure in skilled golfers. They varied anxiety level and putting condition in a 2 × 3 within-group design. Anxiety level (low or high) was varied with a competition being introduced following the low-anxiety trials. The putting conditions were thinking of cue words about either putting technique or irrelevant items, or a single swing thought such as “smooth.” Mean distance from hole was computed for the 10 putts in each condition. The main effect for anxiety was not significant. What does this mean about the marginal means?
The marginal means for the two anxiety conditions are not significantly different.
Yan and Sengupta (2011) examined the effects of price, attractiveness, and consumer on the perceived tastiness and expensiveness of a dish of fried rice. The study was a 2 × 2 × 2 design that varied price (inexpensive or expensive), picture (attractive or unattractive), and consumer (self or classmate) in a between-subjects design. What is the dependent variable?
tastiness and expensiveness
After reading a report by Rockoff (2010), Yingying is studying the effects of others present and their roles on the rate of gambling bets using a simulated slot machine. Her levels of others present are one, two, or six. Her levels of roles are gamblers and observers. She constructs a 2 × 3 table of her results of average time between bets. There are two rows for the roles and three columns for the others present. The values in the first row are 10, 20, and 20 and in the second row are 20, 10, and 10. Describe her results.
main effect of role, no effect of others present, and an interaction
What are the two main reasons to use factorial designs?
to test limits and to test theories
In a factorial experiment, which is the most important effect?
an interaction
Which of the following would not be a cue that the study was a factorial design in a popular press article?
reference to a peer-reviewed journal
A recent study (Koordeman et al., 2011), conducted in the Netherlands, on the effects of commercials for alcohol or alcohol consumption in the movie theater, found that young adults who consume large amounts of alcohol each week are influenced by the commercials, whereas young adults who consume small amounts of alcohol each week were not influenced. Participants saw one of two types of beverage commercials: alcoholic or nonalcoholic. Their consumption of alcohol during the movie was then measured. Finally, they completed a questionnaire on their drinking habits. What type of design is this?
independent-groups factorial
Yan and Sengupta (2011) examined the effects of price, attractiveness, and consumer on the perceived tastiness and expensiveness of a dish of fried rice. The study was a 2 × 2 × 2 design that varied price (inexpensive or expensive), picture (attractive or unattractive), and consumer (self or classmate) in a between-subjects design. A main effect of price and a main effect of picture were found. It was found that the picture had a greater impact on tastiness/expensiveness judgments in self than in classmate. What type of interaction does this describe?
a two-way interaction between picture and consumer
After reading a report by Rockoff (2010), Yingying is studying the effects of others present and their roles on the rate of gambling bets using a simulated slot machine. Her levels of others present are one, two, or six. Her levels of roles are gamblers and observers. She constructs a 2 × 3 table of her results of average time between bets. There are two rows for the roles and three columns for the others present. The values in the first row are 10, 15, and 20 and in the second row are 20, 15, and 10. Describe her results.
no effect of role, no effect of others present, and an interaction
What differences need to be investigated when a three-way design is used?
three main effects, three two-way interactions, and a three-way interaction
Gucciardi and Dimmock (2008) reported on an experiment on choking under pressure in skilled golfers. They varied anxiety level and putting condition in a 2 × 3 within-group design. Anxiety level (low or high) was varied with a competition being introduced following the low-anxiety trials. The putting conditions were thinking of cue words about either putting technique, irrelevant items, or a single swing thought such as “smooth.” Mean distance from hole was computed for the 10 putts in each condition. High anxiety increased distance in the technique condition but not in the other two conditions. What does this describe?
a two-way interaction between anxiety and condition
Gucciardi and Dimmock (2008) reported on an experiment on choking under pressure in skilled golfers. They varied anxiety level and putting condition in a 2 × 3 within-group design. Anxiety level (low or high) was varied with a competition with financial compensation being introduced following the low anxiety-level performance. The putting conditions were thinking of cue words about putting technique, thinking of irrelevant cue words, and thinking about a single swing thought such as “smooth.” Mean distance from hole was computed for the 10 putts in each condition. How many cells was each golfer in?
6
When authors of a research article are describing just the results of a factorial study, which of these terms would you not expect to see?
correlation
To achieve a goal of 20 observations per cell in a 2 × 2 × 3 mixed experiment with the first two factors run within groups and the last factor run between groups, what would be the number of participants needed?
60
How many independent variables and how many cells are there in a 2 × 3 × 4 study?
3 independent variables, 24 cells
Gucciardi and Dimmock (2008) reported on an experiment on choking under pressure in skilled golfers. They varied anxiety level and putting condition in a 2 × 3 within-group design. Anxiety level (low or high) was varied with a competition being introduced following the low-anxiety trials. The putting conditions were thinking of cue words about either putting technique, irrelevant items, or a single swing thought such as “smooth.” Mean distance from hole was computed for the 10 putts in each condition. What are all the differences that must be examined?
two main effects and one interaction
Which of the following is a participant variable?
all of the above
Yan and Sengupta (2011) examined the effects of price, attractiveness, and consumer on the perceived tastiness and expensiveness of a dish of fried rice. The study was a 2 × 2 × 2 design that varied price (inexpensive or expensive), picture (attractive or unattractive), and consumer (self or classmate) in a between-subjects design. How many cells are there in this study?
8
Gucciardi and Dimmock (2008) reported on an experiment on choking under pressure in skilled golfers. They varied anxiety level and putting condition in a 2 × 3 within-group design. Anxiety level (low or high) was varied with a competition with financial compensation being introduced following the low anxiety-level performance. The putting conditions were thinking of cue words about putting technique, thinking of irrelevant cue words, and thinking about a single swing thought such as “smooth.” Mean distance from hole was computed for the 10 putts in each condition. What is the dependent variable?
mean distance from hole
Yan and Sengupta (2011) examined the effects of price, attractiveness, and consumer on the perceived tastiness and expensiveness of a dish of fried rice. The study was a 2 × 2 × 2 design that varied price (inexpensive or expensive), picture (attractive or unattractive), and consumer (self or classmate) in a between-subjects design. A main effect of price and a main effect of picture were found. It was found that the impact of price on tastiness/expensiveness judgments was weaker in the self than in the classmate. What type of interaction does this describe?
a two-way interaction between price and consumer
What is it called when the effect of one independent variable depends on the level of the other independent variable?
interaction
Yan and Sengupta (2011) examined the effects of price, attractiveness, and consumer on the perceived tastiness and expensiveness of a dish of fried rice. The study was a 2 × 2 × 2 design that varied price (inexpensive or expensive), picture (attractive or unattractive), and consumer (self or classmate) in a between-subjects design. Which variable is a participant variable?
all of them are manipulated
interaction effect
a result from a factorial design, in which the difference in the levels of one independent variable changes, depending on the level of the other independent variable; a difference in differences.
factorial design
A study in which there are two or more independent variables, or factors.
cell
a condition in an experiment; in a simple experiment, it can represent the level of one independent variable; in a factorial design, it represents one of the possible combinations of two independent variables.
participant variable
a variable such as age, gender, or ethnicity whose levels are selected (i.e., measured), not manipulated.
main effect
In a factorial design, the overall effect of one independent variable on the dependent variable, averaging over the levels of the other independent variable.
marginal means
In a factorial design, the arithmetic means for each level of an independent variable, averaging over the levels of another independent variable.
What do we use a factorial design to analyze?
We use a factorial design for experiments with multiple independent variables.
Why are factorial designs useful?
they help us look at a combination of variables at the same time, and observe situations that are closer to reality
The simplest possible factorial ANOVA is a —- design.
2*2 design
In the shorthand notation 2*2 design the number of numbers tells us what? The value of each number tells us what?
the amount of IVs. How many levels each Iv has
Define main effect.
The sole effect of one IV in a factorial design
Define interaction.
Joint simultaneous effect on the DV of more than one IV
What is a mixed assignment?
When we have one IV with independent groups and another IV with correlated groups
Factorial designs in which both IV’s involve random assignment are called ——- designs.
completely randomized designs
Factorial designed experiments in which all participant groups for all IV’s have been formed through nonrandom assignment are called ——— designs.
completely within-groups designs
In a repeated measures experiment for a factorial design the participants must do what? (actually for any design)
the participants must participate in each treatment combination
Name a difference between a multiple group design and a factorial design.
We have to interpret interaction effects in a factorial design and we do not need to do that in a multiple group design experiment.
Name an advantage in regards to experimental questions that is attained in factorial design experiment?
The number of questions we can ask in a factorial experiment increases dramatically.
———– research uses a measured rather than a manipulated IV.
ex post facto research
Name 3 factorial designs.
factorial ANOVA, two-way ANOVA, three-way ANOVA, X by Y
3 names for designs that use random assignment for all IV’s.
completely randomized, completely between-subjects, completely between-groups
3 names for designs that use matching or repeated measures.
Randomized block, completely within-subjects, completely within groups
designs that use a mixture of nonrandom and random assignment can be called.( 2 names)
mixed factorial or split-plot factorial
treatment variability is the same as ——– variability.
between groups variability
Define marginal significance.
refers to results in which the p-value is between 5% and 10%.
What is a Type I error?
accepting the experimental hypothesis when the null hypothesis is true.
What is a Type II error?
accepting the null hypothesis when the experimental hypothesis is true
What is programmatic research?
research that refers to a series of experiments that deal with a related topic or question.