Question 1

To display the relationship between per capita yearly liquor consumption and liver disease death rates per 100,000 people in each of 29 countries, a good choice of a graph would be a:

Accepted Answer

A)   pie chart.
B)   boxplot.
C)   histogram.
D)   line graph.
E)   scatterplot.F) D) and E)
G) A) and B)

Question 2

Consider the following data:

The correlation coefficient r is

Accepted Answer

A)   7.6.
B)   0.0
C)   1.0.
D)   -0.6.
E)   -1.0.F) B) and D)
G) A) and D)

Question 3

You calculate the correlation between height and weight for a simple random sample of 50 students from your college. Another student does the same for a simple random sample of 200 students from the college. The other student should get

Accepted Answer

A)   a correlation greater than 1.
B)   a correlation less than -1.
C)   a higher value for the correlation.
D)   a lower value for the correlation.
E)   about the same value for the correlation.F) A) and D)
G) A) and C)

Question 4

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

Accepted Answer

A)   Carat weight of a diamond and its price
B)   Number of courses failed and college grade point average
C)   Amount of food eaten and hunger level
D)   Internet connection speed and time to download a movie fileE) A) and D)
F) C) and D)

Question 5

Which of the following pairs of variables is most likely to show a positive correlation?

Accepted Answer

A)   number of classes a senior has failed and number of job offers he or she receives
B)   a car's maximum speed and its gas mileage (miles per gallon) 
C)   TV screen size (diagonal)  in inches and its cost (in dollars) 
D)   time since removing a dish from the stove and the dish's temperature.E) All of the above
F) B) and C)

Question 6

You read that "the correlation between spending on schools (dollars per pupil)  and median score on student achievement tests is r = 0.08." This means that

Accepted Answer

A)   school districts that spend a lot have higher scores than low-spending districts, and this effect is quite strong.
B)   school districts that spend a lot have lower scores than low-spending districts, and the effect is quite strong.
C)   school districts that spend a lot have somewhat higher scores than low-spending districts, but the effect is weak.
D)   school districts that spend a lot have somewhat lower scores than low-spending districts, but the effect is weak.E) None of the above
F) A) and C)

Question 7

A nutrition study measured 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. Which variable would one put on the horizontal axis of a scatterplot of the data?

Accepted Answer

A)   One would put the BMI score because it is the response variable.
B)   One would put the BMI score because it is the explanatory variable.
C)   One would put helpings of vegetables because it is the response variable.
D)   One would put helpings of vegetables because it is the explanatory variable.
E)   It makes no difference because there is no explanatory-response distinction in this study.F) B) and E)
G) B) and C)

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.  There is a student whose measurements were outliers in the data set. The height of this student was about

Accepted Answer

A)  56.
B)  65.
C)  70.
D)  73.
E)   178.F) A) and E)
G) A) and B)

Question 9

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.  The scatterplot above shows

Accepted Answer

A)   a moderately strong negative straight-line relationship between number of beers and BAC.
B)   a weak negative straight-line relationship between number of beers and BAC.
C)   almost no relationship between number of beers and BAC.
D)   a weak positive straight-line relationship between number of beers and BAC.
E)   a moderately strong positive straight-line relationship between number of beers and BAC.F) A) and B)
G) All of the above

Question 10

Which correlation indicates almost no straight-line relationship?

Accepted Answer

A)   -0.84
B)   0.75
C)   1.5
D)   0.04
E)   0.99F) None of the above
G) A) and B)

Question 11

The correlation between two variables is of -0.18. One can conclude that:

Accepted Answer

A)   an increase in one variable causes a small decrease in the other variable.
B)   there is a strong, positive association between the two variables.
C)   there is a strong, negative association between the two variables.
D)   there is a positive association between the variables, but it is weak.
E)   there is a negative association between the variables, but it is weak.F) B) and D)
G) None of the above

Question 12

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.
In a scatterplot of her data:

Accepted Answer

A)   hours of political debate watching should be on the horizontal axis.
B)   antacid sales should be on the horizontal axis.
C)   it makes no difference which is horizontal.
D)   a scatterplot is not an appropriate type of graph for these data.E) All of the above
F) C) and D)

Question 13

The scout troop is selling brownies for $4 per plate (no sales tax.)  If the explanatory variable was the number of plates of brownies a customer purchased and the response was the amount paid, what would be the correlation between the number of plates and amount paid?

Accepted Answer

A)   The correlation cannot be determined from the information provided.
B)   $4
C)   0.25
D)   1.0
E)   4.0F) All of the above
G) B) and E)

Question 14

A study found that the size of the police force and the number of churches in towns across the United States are positively associated. This means that:

Accepted Answer

A)   towns with few churches tend to have a small police force.
B)   towns with many churches tend to have a large police force.
C)   towns with few churches tend to have a large police force.
D)   towns with many churches tend to have a small police force.
E)   Both "towns with few churches tend to have a small police force" and "towns with many churches tend to have a large police force" are correct.F) B) and C)
G) None of the above

Question 15

Which of the following statements about correlation is false?

Accepted Answer

A)   The value of correlation coefficient is heavily influenced by outliers.
B)   The correlation coefficient can never be larger than 1.
C)   The correlation coefficient measures how tightly the points in a scatterplot cluster about a straight line.
D)   The correlation coefficient cannot be 0.E) B) and D)
F) All of the above

Question 16

A study is conducted to determine if there is a relationship between height (inches)  and annual income (dollars)  among executives at large companies in the United States. Which of the following statements about the descriptive statistics for the study data is not true?

Accepted Answer

A)   The correlation is measured in inches per dollar.
B)   The standard deviation of the incomes is measured in dollars.
C)   The standard deviation of the heights is measured in inches.
D)   The median income is measured in dollars.
E)   Both "the standard deviation of the incomes is measured in dollars" and "the standard deviation of the heights is measured in inches" are correct.F) All of the above
G) C) and D)

Question 17

A random sample of patients who attended a clinic was selected. The age of the patient (years)  and the number of days since the last visit were collected and are displayed in the figure.  Describe the association between "Age of Patient" and "Days Since Last Visit."

Accepted Answer

A)   There is a fairly strong, positive, straight-line association.
B)   There is a fairly strong, negative, straight-line association.
C)   There is a fairly weak, positive, straight-line association.
D)   There is a fairly weak, negative, straight-line association.E) A) and B)
F) All of the above

Question 18

A random sample of patients who attended a clinic was selected. The age of the patient (years)  and the number of days since the last visit were collected and are displayed in the figure.  A plausible value of the correlation coefficient for the data displayed is

Accepted Answer

A)   -0.40.
B)   -0.25.
C)   0.00.
D)   +0.75.
E)   -0.90.F) All of the above
G) D) and E)

Question 19

An agricultural economist says that the correlation between corn prices and rainfall during the growing season is r = -0.7. This means that:

Accepted Answer

A)   when rainfall is above average, corn prices also tend to be above average.
B)   there is almost no relation between rainfall amount and corn prices.
C)   when rainfall is above average, corn prices tend to be below average.
D)   the economist is confused because correlation makes no sense in this situation.E) A) and B)
F) A) and C)

Question 20

A study of home heating costs collects data on the size of houses and the monthly cost to heat the houses with natural gas. Here are the data:

A friend tells you that the correlation for the data is r = 0.99984. You conclude from this number that

Accepted Answer

A)   larger houses cost more to heat than smaller houses, and the relationship is almost perfectly straight.
B)   smaller houses cost more to heat than larger houses, and the relationship is almost perfectly straight.
C)   larger houses cost more to heat than smaller houses, but the relationship is not very strong.
D)   smaller houses cost more to heat than larger houses, but the relationship is not very strong.
E)   your friend made a mistake, because the value of r is impossible.F) B) and D)
G) C) and D)

Exam 14: Describing Relationships: Scatterplots and Correlation

Correct Answer
verified

A nutrition study measured 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. Which variable would one put on the horizontal axis of a scatterplot of the data?

Correct Answer
verified

The correlation between two variables is of -0.18. One can conclude that:

Correct Answer
verified

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. In a scatterplot of her data:

Correct Answer
verified

Which correlation indicates almost no straight-line relationship?

Correct Answer
verified

Which of the following statements about correlation is false?

Correct Answer
verified

A random sample of patients who attended a clinic was selected. The age of the patient (years) and the number of days since the last visit were collected and are displayed in the figure. Describe the association between "Age of Patient" and "Days Since Last Visit."

Correct Answer
verified

A study of home heating costs collects data on the size of houses and the monthly cost to heat the houses with natural gas. Here are the data: A friend tells you that the correlation for the data is r = 0.99984. You conclude from this number that

Correct Answer
verified

To display the relationship between per capita yearly liquor consumption and liver disease death rates per 100,000 people in each of 29 countries, a good choice of a graph would be a:

Correct Answer
verified

You read that "the correlation between spending on schools (dollars per pupil) and median score on student achievement tests is r = 0.08." This means that

Correct Answer
verified

A random sample of patients who attended a clinic was selected. The age of the patient (years) and the number of days since the last visit were collected and are displayed in the figure. A plausible value of the correlation coefficient for the data displayed is

Correct Answer
verified

An agricultural economist says that the correlation between corn prices and rainfall during the growing season is r = -0.7. This means that:

Correct Answer
verified

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

Correct Answer
verified

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. The height of this student was about

Correct Answer
verified

You calculate the correlation between height and weight for a simple random sample of 50 students from your college. Another student does the same for a simple random sample of 200 students from the college. The other student should get

Correct Answer
verified

Which of the following pairs of variables is most likely to show a positive correlation?

Correct Answer
verified

The scout troop is selling brownies for $4 per plate (no sales tax.) If the explanatory variable was the number of plates of brownies a customer purchased and the response was the amount paid, what would be the correlation between the number of plates and amount paid?

Correct Answer
verified

Consider the following data: The correlation coefficient r is

Correct Answer
verified

A study found that the size of the police force and the number of churches in towns across the United States are positively associated. This means that:

Correct Answer
verified

A study is conducted to determine if there is a relationship between height (inches) and annual income (dollars) among executives at large companies in the United States. Which of the following statements about the descriptive statistics for the study data is not true?

Correct Answer
verified

Exam 14: Describing Relationships: Scatterplots and Correlation

Correct AnswerverifiedShow Answer

A nutrition study measured 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. Which variable would one put on the horizontal axis of a scatterplot of the data?

Correct AnswerverifiedShow Answer

The correlation between two variables is of -0.18. One can conclude that:

Correct AnswerverifiedShow Answer

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. In a scatterplot of her data:

Correct AnswerverifiedShow Answer

Which correlation indicates almost no straight-line relationship?

Correct AnswerverifiedShow Answer

Which of the following statements about correlation is false?

Correct AnswerverifiedShow Answer

A random sample of patients who attended a clinic was selected. The age of the patient (years) and the number of days since the last visit were collected and are displayed in the figure. Describe the association between "Age of Patient" and "Days Since Last Visit."

Correct AnswerverifiedShow Answer

A study of home heating costs collects data on the size of houses and the monthly cost to heat the houses with natural gas. Here are the data: A friend tells you that the correlation for the data is r = 0.99984. You conclude from this number that

Correct AnswerverifiedShow Answer

To display the relationship between per capita yearly liquor consumption and liver disease death rates per 100,000 people in each of 29 countries, a good choice of a graph would be a:

Correct AnswerverifiedShow Answer

You read that "the correlation between spending on schools (dollars per pupil) and median score on student achievement tests is r = 0.08." This means that

Correct AnswerverifiedShow Answer

A random sample of patients who attended a clinic was selected. The age of the patient (years) and the number of days since the last visit were collected and are displayed in the figure. A plausible value of the correlation coefficient for the data displayed is

Correct AnswerverifiedShow Answer

An agricultural economist says that the correlation between corn prices and rainfall during the growing season is r = -0.7. This means that:

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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. The height of this student was about

Correct AnswerverifiedShow Answer

You calculate the correlation between height and weight for a simple random sample of 50 students from your college. Another student does the same for a simple random sample of 200 students from the college. The other student should get

Correct AnswerverifiedShow Answer

Which of the following pairs of variables is most likely to show a positive correlation?

Correct AnswerverifiedShow Answer

The scout troop is selling brownies for $4 per plate (no sales tax.) If the explanatory variable was the number of plates of brownies a customer purchased and the response was the amount paid, what would be the correlation between the number of plates and amount paid?

Correct AnswerverifiedShow Answer

Consider the following data: The correlation coefficient r is

Correct AnswerverifiedShow Answer

A study found that the size of the police force and the number of churches in towns across the United States are positively associated. This means that:

Correct AnswerverifiedShow Answer

A study is conducted to determine if there is a relationship between height (inches) and annual income (dollars) among executives at large companies in the United States. Which of the following statements about the descriptive statistics for the study data is not true?

Correct AnswerverifiedShow Answer

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