Question 1

Which of the statements does not contain a statistical blunder?

Accepted Answer

A)  There is a strong negative correlation between a person's sex and the amount that he or she pays for automobile insurance. 
B)  The mean height of young women is 64 inches, and the correlation between their heights and weights is 0.6 inches. 
C)  The correlation between height and weight for adult females is about r = 1.2. 
D)  All three prior statements contain blunders. 
A)  There is a strong negative correlation between a person's sex and the amount that he or she pays for automobile insurance. 
B)  The mean height of young women is 64 inches, and the correlation between their heights and weights is 0.6 inches. 
C)  The correlation between height and weight for adult females is about r = 1.2. 
D)  All three prior statements contain blunders. D

Question 2

A random sample of statistics students was selected. The heights (inches) and the weights (pounds) of the students were collected and are displayed in the figure below.   There is a student whose measurements were outliers in the data set. What do you expect will happen to the correlation if that student's measurements are removed?

Accepted Answer

A)  The correlation will be greater than (further from zero) it was. 
B)  The correlation will be less than (closer to zero) it was. 
C)  The correlation will remain the same as it was. 
D)  There is not enough information to determine how the correlation might change. 
A)  The correlation will be greater than (further from zero) it was. 
B)  The correlation will be less than (closer to zero) it was. 
C)  The correlation will remain the same as it was. 
D)  There is not enough information to determine how the correlation might change. A

Question 3

A random sample of statistics students was selected. The heights (inches) and the weights (pounds) of the students were collected and are displayed in the figure below.   What is the approximate correlation between these two variables?

Accepted Answer

A)  About -0.95 
B)  About -0.72 
C)  Close to 0 
D)  About 0.72 
E)  About 0.95 
A)  About -0.95 
B)  About -0.72 
C)  Close to 0 
D)  About 0.72 
E)  About 0.95 D

Question 4

Which statistical measure is not strongly affected by a few outliers in the data?

Accepted Answer

A)  The mean 
B)  The median 
C)  The standard deviation 
D)  The correlation coefficient 
A)  The mean 
B)  The median 
C)  The standard deviation 
D)  The correlation coefficient

Question 5

Which of the following are most likely to be negatively correlated?

Accepted Answer

A)  The total floor space and the price of an apartment in New York 
B)  The percentage of body fat and the time it takes to run a mile for male college students 
C)  The heights and yearly earnings of 35-year-old U.S. adults 
D)  The prices and the weights of all racing bicycles sold last year in Chicago 
A)  The total floor space and the price of an apartment in New York 
B)  The percentage of body fat and the time it takes to run a mile for male college students 
C)  The heights and yearly earnings of 35-year-old U.S. adults 
D)  The prices and the weights of all racing bicycles sold last year in Chicago

Question 6

A study found correlation r = 0.43 between high school math grades (on a 0 to 100 scale) and income 10 years after high school. This means that

Accepted Answer

A)  people with high math grades tend to have higher income than people with low math grades. 
B)  people with low math grades tend to have higher income than people with high math grades. 
C)  there is almost no association between math grades and income. 
D)  a mistake has been made because a correlation cannot be 0.43. 
E)  a mistake has been made because a correlation between math grades and income makes no sense. 
A)  people with high math grades tend to have higher income than people with low math grades. 
B)  people with low math grades tend to have higher income than people with high math grades. 
C)  there is almost no association between math grades and income. 
D)  a mistake has been made because a correlation cannot be 0.43. 
E)  a mistake has been made because a correlation between math grades and income makes no sense.

Question 7

An education researcher measured the IQ test scores of 78 seventh-grade students in a rural school, and also their school grade point average (GPA) measured on a 12-point scale. Here is a graph of GPA versus IQ for these students:   The graph shows

Accepted Answer

A)  a clear positive association. 
B)  very little association. 
C)  a clear negative association. 
D)  a skewed distribution. 
A)  a clear positive association. 
B)  very little association. 
C)  a clear negative association. 
D)  a skewed distribution.

Question 8

A random sample of statistics students was selected. The heights (inches) and the weights (pounds) of the students were collected and are displayed in the figure below.   What is the approximate correlation between these two variables?

Accepted Answer

A)  About -0.95 
B)  About -0.72 
C)  Close to 0 
D)  About 0.72 
E)  About 0.95 
A)  About -0.95 
B)  About -0.72 
C)  Close to 0 
D)  About 0.72 
E)  About 0.95

Question 9

According to the USA Today web page that tracks such occurrences, NFL quarterbacks are arrested less often (on average) than running backs, who, in turn, are arrested less often than linemen. The correlation coefficient r between a player's position and his number of arrests:

Accepted Answer

A)  is positive. 
B)  is near zero. 
C)  is negative. 
D)  makes no sense. 
A)  is positive. 
B)  is near zero. 
C)  is negative. 
D)  makes no sense.

Question 10

How well does the number of beers a student drinks predict his or her blood alcohol content? Sixteen student volunteers at The Ohio State University drank a randomly assigned number of cans of beer. Thirty minutes later, a police officer measured their blood alcohol content (BAC). A scatterplot of the data appears below.   A plausible value of the correlation between number of beers and blood alcohol content, based on the scatterplot, is

Accepted Answer

A)  r = -0.85. 
B)  r = -0.3. 
C)  r close to 0. 
D)  r = 0.3. 
E)  r = 0.85. 
A)  r = -0.85. 
B)  r = -0.3. 
C)  r close to 0. 
D)  r = 0.3. 
E)  r = 0.85.

Question 11

An education researcher measured the IQ test scores of 78 seventh-grade students in a rural school, and also their school grade point average (GPA) measured on a 12-point scale. Here is a graph of GPA versus IQ for these students:   The IQ score of the student who has the lowest GPA is about

Accepted Answer

A) 103. 
B)  0.6. 
C) 72. 
D)  7.2. 
A) 103. 
B)  0.6. 
C) 72. 
D)  7.2.

Question 12

A nutrition study measuring how many helpings of vegetables each of 125 grade school children were served each week during a school year and their body mass index (BMI) scores found r = -0.13. This tells that:

Accepted Answer

A)  children who ate more vegetables tend to have lower BMI scores, but it is a weak association. 
B)  children who ate more vegetables tend to have lower BMI scores, and it is a strong association. 
C)  children who ate more vegetables tend to have higher BMI scores, but it is a weak association. 
D)  children who ate more vegetables tend to have higher BMI scores, and it is a strong association. 
A)  children who ate more vegetables tend to have lower BMI scores, but it is a weak association. 
B)  children who ate more vegetables tend to have lower BMI scores, and it is a strong association. 
C)  children who ate more vegetables tend to have higher BMI scores, but it is a weak association. 
D)  children who ate more vegetables tend to have higher BMI scores, and it is a strong association.

Question 13

Which of these statements is true of the correlation r?

Accepted Answer

A)  r can only take values 0 or greater than 0. 
B)  r can only take values between -1 and 1, inclusive. 
C)  r describes only straight-line relationships. 
D)  Both "r can only take values 0 or greater than 0" and "r describes only straight-line relationships." are correct. 
E)  Both "r can only take values between -1 and 1, inclusive" and "r describes only straight-line relationships" are correct. 
A)  r can only take values 0 or greater than 0. 
B)  r can only take values between -1 and 1, inclusive. 
C)  r describes only straight-line relationships. 
D)  Both "r can only take values 0 or greater than 0" and "r describes only straight-line relationships." are correct. 
E)  Both "r can only take values between -1 and 1, inclusive" and "r describes only straight-line relationships" are correct.

Question 14

All 753 students in grades 1 through 6 in an elementary school are given a math test that was designed for third graders. The heights of all 753 students are also recorded. We expect to see _______________ between height and test score.

Accepted Answer

A)  positive association 
B)  little or no association 
C)  negative association 
D)  either positive or negative association (but it's hard to predict which) 
A)  positive association 
B)  little or no association 
C)  negative association 
D)  either positive or negative association (but it's hard to predict which)

Question 15

The numerical value of a correlation coefficient can be

Accepted Answer

A)  any number. 
B)  zero or any positive number. 
C)  any number between 0 and 1. 
D)  any number between -1 and 1. 
E)  any number between -1 and 1 other than 0. 
A)  any number. 
B)  zero or any positive number. 
C)  any number between 0 and 1. 
D)  any number between -1 and 1. 
E)  any number between -1 and 1 other than 0.

Question 16

In a scatterplot we can see

Accepted Answer

A)  a display of the five-number summary. 
B)  whether or not we have a simple random sample. 
C)  the shape, center, and spread of the distribution of a quantitative variable. 
D)  the form, direction, and strength of a relationship between two quantitative variables. 
A)  a display of the five-number summary. 
B)  whether or not we have a simple random sample. 
C)  the shape, center, and spread of the distribution of a quantitative variable. 
D)  the form, direction, and strength of a relationship between two quantitative variables.

Question 17

An analyst gathers data on the number of hours of political debates watched per week and the sales of antacids. She expects that political debate watching will help explain antacid sales.
The plot of the data in the preceding question shows that people who watch more political debates tend to buy more antacids. The analyst calculates the correlation r between hours of debates and antacids purchased. A plausible value is:

Accepted Answer

A)  r = -1. 
B)  r = -0.4. 
C)  r = 0. 
D)  r = 0.4. 
A)  r = -1. 
B)  r = -0.4. 
C)  r = 0. 
D)  r = 0.4.

Question 18

Which of these is not true of the correlation r between the weight in pounds and gas mileage in miles-per-gallon for a sample of pickup trucks?

Accepted Answer

A)  r must take a value between -1 and 1. 
B)  r is measured in pounds. 
C)  If heavier pickup trucks tend to also get lower gas mileage, then r < 0. 
D)  r would not change if we measured these trucks in kilograms instead of pounds. 
E)  Both "r is measured in pounds" and "r would not change if we measured these trucks in kilograms instead of pounds" are correct. 
A)  r must take a value between -1 and 1. 
B)  r is measured in pounds. 
C)  If heavier pickup trucks tend to also get lower gas mileage, then r < 0. 
D)  r would not change if we measured these trucks in kilograms instead of pounds. 
E)  Both "r is measured in pounds" and "r would not change if we measured these trucks in kilograms instead of pounds" are correct.

Question 19

Which of the values below is impossible for the descriptive measure in question?

Accepted Answer

A)  r = -1.25 
B) 
  = -0.2 
C)  s = -3.4 
D)  Both r = -1.25 and s = -3.4 are correct. 
E)  Both
  = -0.2 and s = -3.4 are correct. 
A)  r = -1.25 
B) 
  = -0.2 
C)  s = -3.4 
D)  Both r = -1.25 and s = -3.4 are correct. 
E)  Both
  = -0.2 and s = -3.4 are correct.

Question 20

An education researcher measured the IQ test scores of 78 seventh-grade students in a rural school, and also their school grade point average (GPA) measured on a 12-point scale. Here is a graph of GPA versus IQ for these students:   One of these numbers is the correlation r between IQ score and GPA. Which is it?

Accepted Answer

A)  r = 0.02 
B)  r = 0.63 
C)  r = 0.95 
D)  r = -0.63 
E)  r = -0.95 
A)  r = 0.02 
B)  r = 0.63 
C)  r = 0.95 
D)  r = -0.63 
E)  r = -0.95

Which of the statements does not contain a statistical blunder?

A random sample of statistics students was selected. The heights (inches) and the weights (pounds) of the students were collected and are displayed in the figure below. What is the approximate correlation between these two variables?

Which statistical measure is not strongly affected by a few outliers in the data?

Which of the following are most likely to be negatively correlated?

A study found correlation r = 0.43 between high school math grades (on a 0 to 100 scale) and income 10 years after high school. This means that

An education researcher measured the IQ test scores of 78 seventh-grade students in a rural school, and also their school grade point average (GPA) measured on a 12-point scale. Here is a graph of GPA versus IQ for these students: The graph shows

A random sample of statistics students was selected. The heights (inches) and the weights (pounds) of the students were collected and are displayed in the figure below. What is the approximate correlation between these two variables?

According to the USA Today web page that tracks such occurrences, NFL quarterbacks are arrested less often (on average) than running backs, who, in turn, are arrested less often than linemen. The correlation coefficient r between a player's position and his number of arrests:

An education researcher measured the IQ test scores of 78 seventh-grade students in a rural school, and also their school grade point average (GPA) measured on a 12-point scale. Here is a graph of GPA versus IQ for these students: The IQ score of the student who has the lowest GPA is about

A nutrition study measuring how many helpings of vegetables each of 125 grade school children were served each week during a school year and their body mass index (BMI) scores found r = -0.13. This tells that:

Which of these statements is true of the correlation r?

All 753 students in grades 1 through 6 in an elementary school are given a math test that was designed for third graders. The heights of all 753 students are also recorded. We expect to see _______________ between height and test score.

The numerical value of a correlation coefficient can be

In a scatterplot we can see

Which of these is not true of the correlation r between the weight in pounds and gas mileage in miles-per-gallon for a sample of pickup trucks?

Which of the values below is impossible for the descriptive measure in question?

Where Do Data Come From

Samples, Good and Bad

What Do Samples Tell Us

Sample Surveys in the Real World

Experiments, Good and Bad

Experiments in the Real World

Data Ethics

Measuring

Do the Numbers Make Sense

Graphs, Good and Bad

Displaying Distributions With Graphs

Normal Distributions

Describing Relationships: Regression, Prediction, and Causation

The Consumer Price Index and Government Statistics

Thinking About Chance

Probability Models

Simulation

The House Edge: Expected Values

What Is a Confidence Interval

What Is a Test of Significance

Use and Abuse of Statistical Inference

Two-Way Tables and the Chi-Square Test

Filters

Exam 14: Describing Relationships: Scatterplots and Correlation

Which of the statements does not contain a statistical blunder?

A random sample of statistics students was selected. The heights (inches) and the weights (pounds) of the students were collected and are displayed in the figure below. What is the approximate correlation between these two variables?

Which statistical measure is not strongly affected by a few outliers in the data?

Which of the following are most likely to be negatively correlated?

A study found correlation r = 0.43 between high school math grades (on a 0 to 100 scale) and income 10 years after high school. This means that

An education researcher measured the IQ test scores of 78 seventh-grade students in a rural school, and also their school grade point average (GPA) measured on a 12-point scale. Here is a graph of GPA versus IQ for these students: The graph shows

A random sample of statistics students was selected. The heights (inches) and the weights (pounds) of the students were collected and are displayed in the figure below. What is the approximate correlation between these two variables?

According to the USA Today web page that tracks such occurrences, NFL quarterbacks are arrested less often (on average) than running backs, who, in turn, are arrested less often than linemen. The correlation coefficient r between a player's position and his number of arrests:

An education researcher measured the IQ test scores of 78 seventh-grade students in a rural school, and also their school grade point average (GPA) measured on a 12-point scale. Here is a graph of GPA versus IQ for these students: The IQ score of the student who has the lowest GPA is about

A nutrition study measuring how many helpings of vegetables each of 125 grade school children were served each week during a school year and their body mass index (BMI) scores found r = -0.13. This tells that:

Which of these statements is true of the correlation r?

All 753 students in grades 1 through 6 in an elementary school are given a math test that was designed for third graders. The heights of all 753 students are also recorded. We expect to see _______________ between height and test score.

The numerical value of a correlation coefficient can be

In a scatterplot we can see

Which of these is not true of the correlation r between the weight in pounds and gas mileage in miles-per-gallon for a sample of pickup trucks?

Which of the values below is impossible for the descriptive measure in question?

Where Do Data Come From

Samples, Good and Bad

What Do Samples Tell Us

Sample Surveys in the Real World

Experiments, Good and Bad

Experiments in the Real World

Data Ethics

Measuring

Do the Numbers Make Sense

Graphs, Good and Bad

Displaying Distributions With Graphs

Normal Distributions

Describing Relationships: Regression, Prediction, and Causation

The Consumer Price Index and Government Statistics

Thinking About Chance

Probability Models

Simulation

The House Edge: Expected Values

What Is a Confidence Interval

What Is a Test of Significance

Use and Abuse of Statistical Inference

Two-Way Tables and the Chi-Square Test

Filters