Types of research

Experimental, Correlation, Clinical

Experiment

An investigation seeking to understand relations of cause and effect. The investigator manipulates the independent variables to measure the RESPONSE of the dependent variable. Shows the causation.

Independent Variables

The variable being manipulated

Dependent Variables

The variable that is being measured

Experimental Group

The group receiving or reacting to the independent variable

Control Group

the group that does not receive the independent variable. The comparison group.

Population

Identified by researchers to be studied

1. Representative Sample

Chosen people from the population since it was too large.

2. Random Sampling

Requires every person in your population to have an equal chance of being chosen to participate.

Randomly Assigned

method of choosing which group, experimental or control, the sample population is placed in.

Single-Blind

The subjects do not know, but the researcher is aware as to which group everyone is in.

Double-Blind

The subject nor the researcher is aware as to which group anyone is in. Third party is usually involved.

Placebo

a seemingly therapeutic object or procedure that causes the control group to believe they are the experimental group.

Correlational Research

Involves assessing the degree of association between two or more variables or characteristics of interest that occur naturally.

Researcher just observes the natrually occuring differences.

Does NOT prove causation.

Researcher just observes the natrually occuring differences.

Does NOT prove causation.

Clinical Research

Often takes the form of case studies.

Case Studies

~Intensive psychological studies of a single individual.

~Conducted under the assumption that an in-depth understanding of single cases will allow for general conclusions about other similar cases

~Conducted under the assumption that an in-depth understanding of single cases will allow for general conclusions about other similar cases

Danger of assessing Case Studies

The individual studied may be atypical of the larger population. To protect against this, the researcher must be sure to generalize.

Generalizable

applicable to similar circumstances because the predictable outcomes of repeated tests

Two important Research Methods Associated with Developmental Psychology

Cross-sectional Studies and Longitudinal Studies

Operational Definition

An important feature of studies.

A precise description of how variables in a study will be observed and measured.

Must be valid (measuring what they are supposed to measure) and reliable (able to be repeated under similar conditions)

A precise description of how variables in a study will be observed and measured.

Must be valid (measuring what they are supposed to measure) and reliable (able to be repeated under similar conditions)

Group matching

Another experimental design technique by which researchers attempt to categorize subjects and ensure that the control group has members similar to those in the experimental group

Naturalistic Observation

Researchers use this to witness and record situations without becoming involved

Descriptive Statistics

summarize data and describe data. Use Central Tendency– Mean (average), Median (middle number), and Mode (most seen quantity). The results are represented on a normal curve

How to read a Normal Distribution Curve

The Mean determines the location of the center of the graph. The standard deviation determines the height and width of the graph.

When the Standard deviation large, the curve is short and wide. When the standard Deviation is small, the curve is tall and skinny.

In skewed distributions, the median is a better indicator of the central tendency. If the graph is skewed to the right, then there are more smaller values. If the graph is skewed to the left, then there are more larger values.

When the Standard deviation large, the curve is short and wide. When the standard Deviation is small, the curve is tall and skinny.

In skewed distributions, the median is a better indicator of the central tendency. If the graph is skewed to the right, then there are more smaller values. If the graph is skewed to the left, then there are more larger values.

Variability

refers to how much the numbers in the set differ from each other. Mean, Median, and Mode don’t tell a lot about it.

Standard Deviation

measures a function of the average dispersion of numbers around the mean and is a commonly used measure of variability

Typical Distribution

68% are within 1 standard deviation above or below the mean.

95% are within 2 standard deviation above or below the mean

95% are within 2 standard deviation above or below the mean

Percentile

Used when reporting scores on standardized exams. They express the standing of one score relative to all other scores in a set of data

Correlation Coefficient

Will describe how the attributes we are studying relate to one another. A numerical value that indicates the degree and direction of the relationship between two variables. Range from +1.00 to -1.00.

Pearson Correlation Coefficient

a descriptive statistic that describes the linear relationship between two attributes.

Positive-Positive=Positive

Positive-Negative=Negative

Positive-Positive=Positive

Positive-Negative=Negative

Inferential Statistics

Allows researchers to test hypotheses about data and to determine how confident they can be in their inferences about the data.

Used to determine our level of confidence in claiming that a given set of results would be extremely unlikely to occur if the result was only up to chance.

Used to determine our level of confidence in claiming that a given set of results would be extremely unlikely to occur if the result was only up to chance.

When experiments are conducted, psychologists typically want to be able to….

generalize the result of the large group (population)

sample

small group of people in the experiment that must be representative

Null hypothesis

a treatment had no effect in an experiment

Alternative hypothesis

treatment did have an effect.

Errors when testing a hypothesis:

Type I Error and Type II Error

Type I Error

refers to the conclusion that a difference exists when in fact this difference does not exist (given most attention).

Type II Error

refers to the conclusion that there is no difference when in fact there is a difference.

p-value

the statistical probability of making a Type I error. Indicates that the results are statistically significant

Stanley Milgram and Ethics

His deception was seen as unethical

What must patients give before an experiment?

an informed consent (participant only agrees after they have been told what the experiment entails)

What must occur after the experiment?

The participant must be debriefed in which they are told the exact purpose of their participation in the research and of any deception that was used.

What must be certain in any experiment for the participant?

Confidentiality

Subfields in Psychology

Applied Psychology and Basic Psychology

Applied Psychology

psychology put directly into practice (therapist meeting with a client. school psychologist)

Basic Psychology

grounded research

Difference between psychologists and psychiatrists

Psychiatry is the study of mental disorders and are medical DOCTORS that have the ability to prescribe medication.