Deck 18: Descriptive Statistics

Question 1

Explain how to construct and interpret a contingency table.

Answer 1

not answered

Question 2

Read and interpret bar graphs, line graphs, and scatter plots.

Answer 2

not answered

Question 3

List the strengths and weaknesses of the mode, median, and mean.

Answer 3

not answered

Question 4

In a grouped frequency distribution, it is important that the intervals:

A) Are overlapping
B) Do not include extreme scores
C) Are no greater than 5 units
D) Are exhaustive

Question 5

Explain the purpose of descriptive statistics.

Question 6

Examine the frequency distribution listed below. The variable is the number of in-service training classes teachers have attended over a two-year period. What is the mode for the number of in-service classes taken by the teachers?

A) 50
B) 0
C) 3
D) 10

Question 7

Explain the difference between the y-intercept and the regression coefficient.
Multiple Choice

Question 8

Distinguish between inferential and descriptive statistics.

Question 9

Describe and interpret the different measures of variability.

Question 10

Explain the impact of skewness on the measures of central tendency.

Question 11

Examine the frequency distribution listed below. The variable is the number of in-service training classes teachers have attended over a two-year period. This frequency distribution is an example of:

A) descriptive statistics.
B) inferential statistics
C) measures of central tendency
D) a contingency table

Question 12

Calculate the range, variance, and standard deviation.

Question 13

Explain the difference between a frequency distribution and a grouped frequency distribution.

Question 14

A table listing the values of a variable and their frequencies of occurrence is called:

A) The standard deviation
B) A point estimate
C) A frequency distribution
D) A scatter plot

Question 15

Explain the difference between simple and multiple regression.

Question 16

In a grouped frequency distribution, it is important that the intervals be:

A) Overlapping
B) No greater than 10 units
C) Mutually exclusive
D) No greater than 5 units

Question 17

Calculate the mode, median, and mean.

Question 18

Explain positive skew and negative skew.

Question 19

Explain percentile ranks and z scores.

Question 20

The purpose of descriptive statistics is to:

A) Make inferences about a population from a sample
B) Test hypotheses
C) Make interval estimates
D) Summarize and explain a set of data

Question 21

A problem with the mode is that:

A) Its value is affected by extreme scores
B) There might be more than one mode
C) It is always the same as the median.
D) Calculating its value is complex.

Question 22

In graphing the frequencies of a single variable (e.g., in a bar graph, histogram, or line graph), the frequencies are put on which axis:

A) X or abscissa
B) Y or ordinate

Question 23

Which will have the highest score value in the distribution?

A) The mode
B) The median
C) The mean
D) The variance

Question 24

The relationship between two quantitative variables is typically represented with a:

A) Line graph
B) Scatter plot
C) Bar graph
D) Frequency distribution

Question 25

What is an advantage of the mean as a measure of central tendency?

A) It is not influenced by extreme scores
B) It is representative even when there is extreme skewness
C) It is the most precise measure of central tendency
D) It can be used with nominal variables

Question 26

The mode is:

A) The arithmetic average
B) The middle score
C) The most frequent score
D) A measure of variability

Question 27

The mean is:

A) The score value that divides the distribution in half
B) The average score
C) The most frequent score
D) A measure of variability

Question 28

What is the median of the following set of scores: 18, 6, 12, 10, 14?

A) 10
B) 14
C) 18
D) 12

Question 29

How is the distribution skewed?

A) Positive skew
B) Negative skew
C) Symmetrical
D) No skew

Question 30

What is a disadvantage of the mode as a measure of central tendency?

A) It is influenced by extreme scores
B) It is imprecise
C) It cannot be easily interpreted
D) It does not take into account the magnitude of all the scores

Question 31

Which will be the best measure of central tendency for these data?

A) The mode
B) The median
C) The mean

Question 32

The median is:

A) The most frequent score
B) The middle score
C) The highest score
D) The average

Question 33

What kind of skew is there in the below distribution?

A) Positive skew
B) Negative skew
C) Symmetrical
D) No skew

Question 34

Below are four sets of intervals for grouped frequency distributions. The data that they are based on has scores that range from 0 to 49. Only one set of intervals meets the necessary criteria for groupings. Pick the one that meets the criteria:

A) 40-49 30-39
20-29
10-19
0-9
B) 40-49 30-39
20-29
10-19
1-9
C) 40-49 30-40
20-30
10-20
0-9
D) 30-40 20-30
10-20
0-10

Question 35

Measures of central tendency provide a:

A) single value that tells you how variable scores are
B) frequency distribution of values
C) single value that tells you about the range of scores
D) single value that is considered most typical of the values of a variable

Question 36

In graphing the relationship between two variables in a scatter plot, which axes contain the independent and dependent variable?

A) X contains the independent variable and Y contains the dependent variable
B) X contains the dependent variable and Y contains the independent variable

Question 37

Which will be the best measure of central tendency for these data?

A) The mode
B) The median
C) The mean
D) The variance

Question 38

Which will have the highest score value in the distribution?

A) The mode
B) The median
C) The mean

Question 39

What is an advantage of the mean as a measure of central tendency?

A) It is not influenced by extreme scores
B) It is representative even when there is extreme skewness
C) It is very stable from sample to sample
D) It can be used with nominal variables

Question 40

When is the median the best measure of central tendency?

A) The data are in a symmetrical distribution
B) When there are a large number of cases
C) There is a great deal of variability in the scores
D) The data are highly skewed

Question 41

Which of the following distributions is negatively skewed?

A)
B)
C)

Question 42

The plus or minus sign before a z score tells you:

A) If a score is above or below the mean
B) The magnitude of the score
C) The correlation
D) The variability

Question 43

The denominator (bottom) of the z score formula is:

A) The standard deviation
B) The difference between a score and the mean
C) The range
D) The mean

Question 44

Measures of variability indicate:

A) Where the modal score lies
B) The median score value
C) The degree of skewness in the distribution
D) How spread out scores are in a distribution

Question 45

The standard deviation is:

A) The square root of the variance
B) A measure of central tendency
C) A theoretical construct
D) An inferential statistic

Question 46

Joe had a percentile rank of 70 on a standardized math test. What does that mean?

A) He did poorly, since he only correctly answered 70% of the questions
B) He did well in that he scored higher than 70% of the people that took the test
C) He did well, in that he answered 70% of the items correctly
D) He did poorly since he only answered 70% of the items that an average individual would answer correctly

Question 47

The range refers to:

A) The difference between the lowest and highest score.
B) The difference between the mean and the median.
C) The mode in a bimodal distribution.
D) The difference between a score and the mean.

Question 48

Approximately what percentage of scores falls within one standard deviation of the mean in a normal distribution?

A) 34%
B) 95%
C) 99%
D) 68%

Question 49

Which of the data points in the following distribution seems to be an outlier: 8, 10, 12, 14, 12, 15, 2000?

A) 8
B) 10
C) 14
D) 2000

Question 50

If a set of scores is very variable, they are said to be __________, whereas when they do not vary a great deal they are said to be___________.

A) Homogeneous, Heterogeneous
B) Heterogeneous, Homogeneous
C) Modal, Median
D) Positively skewed, Negatively skewed

Question 51

If your grade on a test was determined by your standing relative to others in a class and you had a score of 90, what class should you most like to be in (hint: which one has the largest z score)?

A) Mean grade = 85, SD = 10
B) Mean grade = 83, SD = 5
C) Mean grade = 80, SD = 20
D) Mean grade = 90, SD = 5

Question 52

A data point that is very atypical of the scores in a distribution is called:

A) The mode
B) The median
C) An outlier
D) A variance

Question 53

What is the variance?

A) The difference between the lowest and highest score
B) The difference between a score and the mean
C) The average squared distance from the mean
D) A measure of central tendency

Question 54

Which of the following distributions is positively skewed?

A)
B)
C)

Question 55

A percentile rank tells you:

A) The percent correct on a test
B) The percent of people who scored better than you
C) The percent of people in a particular group who score below your score value
D) How far above or below the mean you are in percentages

Question 56

Which of the following distributions is closest to being symmetrical?

A)
B)
C)

Question 57

What is the range of the following set of data: 10, 20, 40, 50, 70, 100, 110?

A) 90
B) 80
C) 10
D) 100

Question 58

Approximately what percentage of scores falls within two standard deviations of the mean in a normal distribution?

A) 34%
B) 95%
C) 99%
D) 68%

Question 59

A z score transforms a raw score into:

A) Percent correct
B) A ratio of right to wrong answers
C) A range
D) Standard deviation units

Question 60

The numerator of the z score formula is:

A) The standard deviation
B) The difference between a score and the mean
C) The range
D) The mean

Question 61

Below are z scores for four people who took a test. Which one scored the highest? John -2.9, Samantha +2.1, Sally +0.1, and Joshua +1.0

A) John
B) Samantha
C) Sally
D) Joshua

Question 62

A contingency table is:

A) A frequency distribution for a single variable
B) A table displaying information in cells formed by the intersection of two or more categorical variables
C) A table containing correlation coefficients
D) A normal curve representation of two variables

Question 63

On an IQ test with a mean of 100 and a standard deviation of 15, what is the z score for someone with an IQ of 70?

A) -1.30
B) -2.00
C) -1.00
D) -13

Question 64

In a regression equation, the Y-intercept defines:

A) The point where the regression line crosses the y-axis
B) The point where the regression line crosses the x-axis
C) The amount of change in the dependent variable per one unit change in the independent variable
D) The amount of change in the independent variable per one unit change in the dependent variable

Question 65

Examine the following table. A researcher is interested in whether learning from instruction that includes video will be more likely to transfer (be applicable in new contexts) than learning that takes place with still photos or a written document. Which statement below is true?

A) The video group was less likely to transfer than the picture group
B) The picture group had the largest number of participants show transfer
C) The picture group was more likely to transfer than the written text group
D) All groups were equally likely to show transfer of learning

Question 66

Examine the following table. A researcher is interested in whether learning from instruction that includes video will be more likely to transfer (be applicable in new contexts) than learning that takes place with still photos or a written document. Is there a likely relationship between instructional group and transfer of learning?

A) Yes
B) No

Question 67

A simple regression examines:

A) How two or more independent variables predict or explain the scores on a dependent variable
B) How to create a graph that shows changes across time
C) How one independent variable is confounded with another independent variable
D) The prediction or explanation of scores on one dependent variable based on the scores from one independent variable

Question 68

A z score of 0.00 means that:

A) A person had zero points on a test
B) A person scored at the mean
C) A person scored below the mean
D) A person scored in the bottom percentile

Question 69

Which statement best captures the relationship between handedness and major?

A) Major is unrelated to handedness
B) Left-handed people are more likely to major in humanities than right-handed people
C) Right-handed people are more likely to major in science than left-handed people
D) Left-handed people are more likely to major in science than right-handed people

Question 70

Let us suppose we are predicting the score on a training posttest from the number of years of education and the score on an aptitude test given before training. Here is the regression equation: Y = 25 + .5X₁ +10X₂,
Where X₁ = years of education and X₂ = aptitude test score.
What does the .5 in front of X₁ tell us?

A) Where the equation crosses the y-axis
B) How much change in posttest score you get per unit change in aptitude test score
C) How much change in the posttest score you get per unit change in years of education
D) How much change in the years of education you get per unit change in posttest score

Question 71

Let us suppose we are predicting the score on a training posttest from the number of years of education and the score on an aptitude test given before training. Here is the regression equation: Y = 25 + .5X₁ +10X₂,
Where X₁ = years of education and X₂ = aptitude test score.
What is the predicted score for someone with 10 years of education and an aptitude test score of 5?

A) 25
B) 50
C) 35
D) 80

Question 72

Which statement below is true?

A) Instructional group is unrelated to transfer of learning
B) The video group was three times more likely to transfer than the text group
C) The video group was less likely to transfer than the picture group
D) The text group was more likely to transfer than the picture group

Question 73

Let us suppose we are predicting the score on a training posttest from the number of years of education and the score on an aptitude test given before training. Here is the regression equation: Y = 25 + .5X₁ +10X₂,
Where X₁ = years of education and X₂ = aptitude test score.
Which of the following are true about this equation?

A) The equation is a simple regression analysis
B) The regression coefficient for aptitude test controls for years of education
C) The equation is in standard score form
D) For every unit change in X₁, there is a 10 unit change in Y

Question 74

Regression analysis involves:

A) Creating a graph that shows changes across time
B) Creating a test where people do not regress toward the mean
C) A statistical procedure used to predict or explain the values of a dependent variable based on the values of one or more independent variables
D) A statistical procedure for analyzing contingency table

Question 75

Below is a contingency table containing frequencies and column percentages that looks at the relationship between handedness and majoring in science versus the humanities. Is there a likely relationship between handedness and major?

A) Yes
B) No

Question 76

What is the difference between the regression coefficient in a simple regression and the regression coefficients in a multiple regression?

A) The simple regression coefficient is always less than one
B) The multiple regression coefficients do not control for other independent variables
C) The simple regression coefficient does not control for other independent variables
D) There are no differences between simple and multiple regression

Question 77

In a normal distribution, 95% of the scores fall between z scores of:

A) -1 thru +1
B) -2 thru +2
C) -3 thru +3
D) 0 thru + 3

Question 78

In a simple regression, the regression coefficient tells you:

A) The mean of the variable.
B) The point where the regression line crosses the x-axis.
C) The amount of change in the dependent variable per unit change in the independent variable.
D) The amount of change in the independent variable per one unit change in the dependent variable.

Question 79

Multiple regression examines:

A) How two or more independent variables predict or explain the scores on a single dependent variable
B) How to create a graph that shows changes across time
C) How one independent variable is confounded with another independent variable
D) The prediction of one dependent variable from one independent variable

Question 80

Below is a regression equation predicting children's math achievement from their parents' education level (years of education). Y = 1 + 2x,
Where x is the number of years of parental education.
What would be the predicted score for a child whose parents had 12 years of education?

A) 15
B) 24
C) 25
D) 3