Winter statistics 1.1 – Flashcards
Unlock all answers in this set
Unlock answersquestion
Statistics
answer
is the science of collecting, organizing, summarizing, and analyzing information to draw or answer questions. In addition, statistics is about providing a measure of confidence in any conclusions.
question
data
answer
a fact or proposition used to draw a conclusion or make a decision. it describe characteristics of an individual
question
Data can be
answer
numerical, as in height, or nonnumerical, as in gender
question
Anecdotal means
answer
that the information being conveyed is based on casual observation, not scientific research
question
population
answer
The entire group of individuals to be studied
question
individual
answer
is a person or object that is a member of the population being studied.
question
sample
answer
is a subset of the population that is being studied.
question
descriptive statistic
answer
it describes the results of the sample without making any general conclusions about the population consist of organizing and summarizing data. describe data through numerical summaries, tables, and graphs.
question
statistic
answer
is a numerical summary of a sample
question
This is an example of what "Suppose 39 of the 50 students stated that they would return the money to theowner.We could present this result by saying the percent of students in the survey that stated they would return the money to the owner is 78%"
answer
Descriptive statistic
question
Inferential statistics
answer
uses methods that take a result from a sample, extend it to the population, and measure the reliability of the result.
question
If we extend the results of our sample to the population and say that the proportion of all students at the school who would return the money is 78%, we are performing
answer
Inferential statistics
question
parameter
answer
is a numerical summary of a population.
question
Suppose the percentage of all students on your campus that own a car is 48.2%. Is this a statistic or parameter?
answer
This value represents a parameter because it is a numerical summary of a population.
question
Suppose a sample of 100 students is obtained, and from this sample we find that 46% own a car. is this a statistic or parameter ?
answer
This value represents a statistic because it is a numerical summary of a sample.
question
convenience samples
answer
Many nonscientific studies are based on Internet surveys or phone-in polls. The results of any study performed using this type of sampling method are not reliable.
question
The Process of Statistics
answer
1. Identify the research objective, 2. Collect the data needed to answer the question(s) posed in (1). 3. Describe the data. 4. Perform inference
question
1. Identify the research objective.
answer
A researcher must determine the question(s) he or she wants answered.The question(s) must be detailed so that it identifies the population that is to be studied.
question
2. Collect the data needed to answer the question(s)
answer
Gaining access to an entire population is often difficult and expensive. When conducting research, we typically look at a sample. The collection of data step is vital to the statistical process, because if the data are not collected correctly, the conclusions drawn are meaningless. Do not overlook the importance of appropriate data-collection processes.
question
3. Describe the data
answer
Obtaining descriptive statistics allows the researcher to obtain an overview of the data and can provide insight as to the type of statistical methods the researcher should use
question
4. Perform inference
answer
Apply the appropriate techniques to extend the results obtained from the sample to the population and report a level of reliability of the results.
question
Variables
answer
are the characteristics of the individuals within the population.
question
Qualitative
answer
categorical, variables allow for classification of individuals based on some attribute or characteristic.
question
Quantitative variables
answer
provide numerical measures of individuals. Arithmetic operations such as addition and subtraction can be performed on the values of a quantitative variable and will provide meaningful results.
question
approach
answer
or a way to look at and organize a problem so that it can be solved
question
Distinguishing between Qualitative and Quantitative Variables (a) Gender
answer
(a) Gender is a qualitative variable because it allows a researcher to categorize the individual as male or female. Notice that arithmetic operations cannot be performed on these attributes.
question
Distinguishing between Qualitative and Quantitative Variables (b) Temperature
answer
(b) Temperature is a quantitative variable because it is numeric, and operations such as addition and subtraction provide meaningful results. For example, 70°F is 10°F warmer than 60°F.
question
Distinguishing between Qualitative and Quantitative Variables (c) Number of days during the past week that a college student aged 21 years or older has had at least one drink
answer
(c) Number of days during the past week that a college student aged 21 years or older had at least one drink is a quantitative variable because it is numeric, and operations such as addition and subtraction provide meaningful results.
question
Distinguishing between Qualitative and Quantitative Variables (d) Zip code
answer
(d) Zip code is a qualitative variable because it categorizes a location. Notice that, even though they are numeric, the addition or subtraction of zip codes does not provide meaningful results.
question
discrete variable
answer
is a quantitative variable that has either a finite number of possible values or a countable number of possible values. The term countable means that the values result from counting, such as 0, 1, 2, 3, and so on.
question
continuous variable
answer
is a quantitative variable that has an infinite number of possible values that are not countable.
question
Distinguishing between Discrete and Continuous Variables (a) The number of heads obtained after flipping a coin five times.
answer
(a) The number of heads obtained by flipping a coin five times would be a discrete variable because we would count the number of heads obtained. The possible values of the discrete variable are 1,2,3,4...
question
Distinguishing between Discrete and Continuous Variables (b) The number of cars that arrive at a McDonald's drive-through between 12:00 P.M. and 1:00 P.M.
answer
(b) The number of cars that arrive at a McDonald's drive-through between 12:00 P.M. and 1:00 P.M. is a discrete variable because its value would result from counting the cars. The possible values of the discrete variable are 0, 1, 2, 3, 4, and so on. Notice that there is no predetermined upper limit to the number of cars that may arrive.
question
Distinguishing between Discrete and Continuous Variables (c) The distance a 2007 Toyota Prius can travel in city driving conditions with a full tank of gas.
answer
(c) The distance traveled is a continuous variable because we measure the distance.
question
The type of variable (qualitative, discrete, or continuous) dictates
answer
the methods that can be used to analyze the data.
question
nominal level of measurement
answer
if the values of the variable name, label, or categorize. In addition, the naming scheme does not allow for the values of the variable to be arranged in a ranked or specific order.
question
ordinal level of measurement
answer
if it has the properties of the nominal level of measurement and the naming scheme allows for the values of the variable to be arranged in a ranked or specific order.
question
interval level of measurement
answer
if it has the properties of the ordinal level of measurement and the differences in the values of the variable have meaning. A value of zero in the interval level of measurement does not mean the absence of the quantity. Arithmetic operations such as addition and subtraction can be performed on values of the variable.
question
ordinal level of measurement
answer
if it has the properties of the ordinal level of measurement and the differences in the values of the variable have meaning. A value of zero in the interval level of measurement does not mean the absence of the quantity. Arithmetic operations such as addition and subtraction can be performed on values of the variable.
question
ratio level of measurement
answer
if it has the properties of the interval level of measurement and the ratios of the values of the variable have meaning. A value of zero in the ratio level of measurement means the absence of the quantity. Arithmetic operations such as multiplication and division can be performed on the values of the variable.
question
Determining the Level of Measurement of a Variable. (a) Gender
answer
(a) Gender is a variable measured at the nominal level because it only allows for categorization of male or female. Plus, it is not possible to rank gender classifications.
question
Determining the Level of Measurement of a Variable. (b) Temperature
answer
(b) Temperature is a variable measured at the interval level because differences in the value of the variable make sense. For example, 70°F is 10°F warmer than 60°F. Notice that the ratio of temperatures does not represent a meaningful result. For example, 60°F is not twice as warm as 30°F. In addition, 0°F does not represent the absence of heat.
question
Determining the Level of Measurement of a Variable. (c) Number of days during the past week that a college student aged 21 years or older has had at least one drink
answer
(c) Number of days during the past week that a college student aged 21 years or older has had at least one drink is measured at the ratio level, because the ratio of two values makes sense and a value of zero has meaning. For example, a student who had four drinks had twice as many drinks as a student who had two drinks.
question
Determining the Level of Measurement of a Variable. (d) Letter grade earned in your statistics class
answer
(d) Letter grade is a variable measured at the ordinal level because the values of the variable can be ranked, but differences in values have no meaning. For example, an A is better than a B, but A - B has no meaning.
question
Validity
answer
of a variable or measurement represents how close to the true value the measurement is. In other words, a variable is valid if it measures what it is supposed to measure.
question
Reliability
answer
of a variable or measurement represents the ability of different measurements of the same individual to yield the same results
question
A(n)_____________ is a person or object that is a member of the population being studied
answer
individual
question
A(n) _____ is a numerical summary of sample. A(n)_____ is a numerical summary of a population.
answer
A(n) statistic is a numerical summary of sample. A(n) parameter is a numerical summary of a population.
question
determine whether the underlined value is a parameter or a statistic. State Government Following the 2006 national midterm election, 18% of the governors of the 50 United States were female.
answer
parameter
question
determine whether the underlined value is a parameter or a statistic. Illegal Drugs In a national survey of high school students (grades 9 to 12), 25% of respondents reported that someone had offered, sold, or given them an illegal drug on school property.
answer
statistic
question
determine whether the underlined value is a parameter or a statistic. Batting Average Ty Cobb is one of Major League Baseball's greatest hitters of all time, with a career batting average of 0.366
answer
parameter
question
determine whether the underlined value is a parameter or a statistic. Hygiene Habits A study of 6,076 adults in public rest rooms (inAtlanta,Chicago,NewYork City,and San Francisco) found that 23% did not wash their hands before exiting.
answer
statistic
question
classify the variable as qualitative or quantitative. Nation of origin
answer
qualitative
question
classify the variable as qualitative or quantitative. Grams of carbohydrates in a doughnut
answer
quantitative
question
classify the variable as qualitative or quantitative. Number of unpopped kernels in a bag of ACT microwave popcorn
answer
quantitative
question
classify the variable as qualitative or quantitative. Phone number
answer
qualitative
question
determine whether the quantitative variable is discrete or continuous. Runs scored in a season by Albert Pujols
answer
discrete
question
determine whether the quantitative variable is discrete or continuous Length (in minutes) of a country song
answer
continuous
question
determine whether the quantitative variable is discrete or continuous Temperature on a randomly selected day in Memphis, Tennessee
answer
continuous
question
determine whether the quantitative variable is discrete or continuous Points scored in an NCAA basketball game
answer
discrete
question
determine the level of measurement of each variable. Nation of origin
answer
Nominal
question
determine the level of measurement of each variable. Volume of water used by a household in a day
answer
Ratio
question
determine the level of measurement of each variable. Highest degree conferred (high school, bachelor's, and so on)
answer
ordinal
question
determine the level of measurement of each variable. Assessed value of a house
answer
Ratio