Deck 9: Correlation and Regression

Question 1

The data below are the temperatures on randomly chosen days during a summer class and the number of
absences on those days. Construct a scatter plot for the data.

Answer 1

Question 2

Identify the explanatory variable and the response variable.
A college counselor wants to determine if the number of hours spent studying for a test can be used to predict
the grades on a test.

Answer 2

explanatory variable: hours studying; response variable: grades on the test

Question 3

The data below are the final exam scores of 10 randomly selected statistics students and the number of hours
they studied for the exam. Construct a scatter plot for the data.

Answer 3

Question 4

Calculate the correlation coefficient, r, for the data below. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | c | } \mathrm { x } & 5 & 7 & 14 & 11 & 9 & 8 & 10 & 12 & 13 & 6 \\\hline \mathrm { y } & 7 & - 10 & 4 & - 7 & - 6 & - 3 & 1 & - 9 & 2 & 3\end{array}$$

A)-0.104
B)-0.132
C)-0.549
D)-0.581

Question 5

In an area of the Midwest, records were kept on the relationship between the rainfall (in inches)and the yield
of wheat (bushels per acre). Construct a scatter plot for the data.

Question 6

A manager wishes to determine the relationship between the number of miles (in hundreds of miles)the
managerʹs sales representatives travel per month and the amount of sales (in thousands of dollars)per month.
Construct a scatter plot for the data.

Question 7

The data below are the average monthly temperatures, in °F, and the monthly natural gas consumption, in ccf,
for a household in northwestern Pennsylvania. Calculate the correlation coefficient, r.

Question 8

Construct a scatter plot for the given data. Determine whether there is a positive linear correlation, negative
linear correlation, or no linear correlation.

Question 9

The data below are the number of absences and the final grades of 9 randomly selected students from a
statistics class. Construct a scatter plot for the data.

Question 10

Given the size of a humanʹs brain, x, and their score on an IQ test, y, would you expect a positive correlation, a negative correlation, or no correlation?

A)no correlation
B)positive correlation
C)negative correlation

Question 11

Identify the explanatory variable and the response variable.
An agricultural business wants to determine if the rainfall in inches can be used to predict the yield per acre on
a wheat farm.

Question 12

Calculate the correlation coefficient, r, for the data below. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | c | } \mathrm { x } & 1 & 3 & 10 & 7 & 5 & 4 & 6 & 8 & 9 & 2 \\\hline \mathrm { y } & 1 & - 4 & - 16 & - 11 & - 7 & - 6 & - 9 & - 14 & - 15 & - 2\end{array}$$

A)-0.995
B)-0.671
C)-0.778
D)-0.885

Question 13

The data below are the ages and systolic blood pressures (measured in millimeters of mercury)of 9 randomly
selected adults. Construct a scatter plot for the data.

Question 14

Given the supply of a commodity, x, and the price of a commodity, y, would you expect a positive correlation, a negative correlation, or no correlation?

A)negative correlation
B)positive correlation
C)no correlation

Question 15

Construct a scatter plot for the given data. Determine whether there is a positive linear correlation, negative
linear correlation, or no linear correlation.

Question 16

In order for applicants to work for the foreign-service department, they must take a test in the language of the
country where they plan to work. The data below show the relationship between the number of years that
applicants have studied a particular language and the grades they received on the proficiency exam. Construct
a scatter plot for the data.

Question 17

Given the length of a humanʹs femur, x, and the length of a humanʹs humerus, y, would you expect a positive correlation, a negative correlation, or no correlation?

A)positive correlation
B)negative correlation
C)no correlation

Question 18

Calculate the correlation coefficient, r, for the data below. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | c | } \mathrm { x } & - 1 & 1 & 8 & 5 & 3 & 2 & 4 & 6 & 7 & 0 \\\hline \mathrm { y } & 0 & 2 & 19 & 11 & 8 & 4 & 9 & 13 & 16 & 2\end{array}$$

A)0.990
B)0.881
C)0.819
D)0.792

Question 19

The data below are the gestation periods, in months, of randomly selected animals and their corresponding life
spans, in years. Construct a scatter plot for the data. Determine whether there is a positive linear correlation, a
negative linear correlation, or no linear correlation.

Question 20

The data below are the gestation periods, in months, of randomly selected animals and their corresponding life
spans, in years. Calculate the correlation coefficient r.

Question 21

The data below are the ages and systolic blood pressures (measured in millimeters of mercury)of 9 randomly selected adults. Calculate the correlation coefficient, r. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | } \text { Age, } \mathrm { x } & 33 & 36 & 40 & 43 & 46 & 48 & 52 & 56 & 60 \\\hline \text { Pressure, } \mathrm { y } & 112 & 116 & 119 & 127 & 138 & 141 & 144 & 146 & 148\end{array}$$

A)0.960
B)0.998
C)0.890
D)0.908

Question 22

In order for applicants to work for the foreign-service department, they must take a test in the language of the country where they plan to work. The data below shows the relationship between the number of years that
Applicants have studied a particular language and the grades they received on the proficiency exam. Calculate
The correlation coefficient, r. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | } \text { Number of years, } \mathrm { x } & 5 & 6 & 6 & 7 & 5 & 8 & 4 & 9 & 5 \\\hline \text { Grades on test, } \mathrm { y } & 52 & 59 & 66 & 73 & 64 & 81 & 49 & 84 & 63\end{array}$$

A)0.934
B)0.911
C)0.891
D)0.902

Question 23

Given a sample with r = 0.823, n = 10, and ? $\alpha$ = 0.05, determine the critical values t0 necessary to test the claim $Q$ ? = 0.

A) $\pm 2.306$
B) $\pm 2.821$
C) $\pm 1.833$
D) $\pm 1.383$

Question 24

Given a sample with r = 0.823 and n = 10, test the significance of the correlation r using α = 0.05 and the claim ρ ρ= 0.

Question 25

For the data below, test the significance of the correlation coefficient using α = 0.05 and the claim ρ = 0.

Question 26

In an area of the Midwest, records were kept on the relationship between the rainfall (in inches)and the yield of wheat (bushels per acre). Calculate the correlation coefficient, r. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | } \text { Rain fall (in inches), } x & 9.5 & 7.8 & 12.4 & 11.5 & 17.8 & 9.3 & 6 & 14.6 & 15 \\\hline \text { Yield (bushels per acre), y } & 45.5 & 41.2 & 53.8 & 54 & 77.4 & 44.2 & 26.9 & 71 & 73.8\end{array}$$

A)0.981
B)0.998
C)0.900
D)0.899

Question 27

Given a sample with r = 0.823, n = 10, and ? $\alpha$ = 0.05, determine the standardized test statistic t necessary to test the claim ? $Q$ = 0. Round answers to three decimal places.

A)4.098
B)3.816
C)2.891
D)1.782

Question 28

Given a sample with r = -0.541, n = 20, and ? $\alpha$ = 0.01, determine the standardized test statistic t necessary to test the claiclaim $\varrho$ = 0. Round answers to three decimal places.

A)-2.729
B)-5.132
C)-4.671
D)-3.251

Question 29

Given a sample with r = -0.765 and n = 22, test the significance of the correlation r using α = 0.02 and the claim ρ = 0.

Question 30

The data below are the temperatures on randomly chosen days during a summer class and the number of absences on those days. Calculate the correlation coefficient, r. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | } \text { Temperature, } \mathrm { x } & 76 & 89 & 95 & 94 & 92 & 102 & 79 & 104 & 84 \\\hline \text { Number of absences, } y & 12 & 16 & 19 & 19 & 17 & 24 & 13 & 24 & 14\end{array}$$

A)0.980
B)0.890
C)0.881
D)0.819

Question 31

Given a sample with r = 0.321 and n = 30, test the significance of the correlation r using α = 0.10 and the claim ρ = 0.

Question 32

Given a sample with r = -0.765, n = 22, and ? $\alpha$ = 0.02, determine the critical values $t _ { 0 }$ necessary to test the claim $Q$ ? = 0.

A) $\pm 2.528$
B) $\pm 2.080$
C) $\pm 2.831$
D) $\pm 1.721$

Question 33

Given a sample with r = -0.541, n = 20, and ? $\alpha$ = 0.01, determine the critical values $t _ { 0 }$ necessary to test the claim $\text { Q }$ ? = 0.

A) $\pm 2.878$
B) $\pm 1.729$
C) $\pm 2.093$
D) $\pm 2.540$

Question 34

Given a sample with r = 0.321, n = 30, and ? $\alpha$ = 0.10, determine the standardized test statistic t necessary to test the claim ? $Q$ = 0. Round answers to three decimal places.

A)1.793
B)3.198
C)2.354
D)2.561

Question 35

A manager wishes to determine the relationship between the number of miles (in hundreds of miles)the manager?s sales representatives travel per month and the amount of sales (in thousands of dollars)per month.
Calculate the correlation coefficient, r. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | } \text { Miles traveled, } \mathrm { x } & 5 & 6 & 13 & 10 & 11 & 18 & 6 & 4 & 14 \\\hline \text { Sales, y } & 30 & 32 & 77 & 61 & 64 & 60 & 47 & 54 & 119\end{array}$$

A)0.632
B)0.561
C)0.717
D)0.791

Question 36

The data below are the final exam scores of 10 randomly selected statistics students and the number of hours they studied for the exam. Calculate the correlation coefficient r. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | c | } \text { Hours, } \mathrm { x } & 2 & 4 & 1 & 7 & 1 & 3 & 3 & 4 & 5 & 2 \\\hline \text { Scores, } y & 68 & 83 & 63 & 91 & 69 & 81 & 88 & 93 & 93 & 74\end{array}$$

A)0.847
B)0.991
C)0.761
D)0.654

Question 37

Given a sample with r = -0.541, n = 20, test the significance of the correlation r using α = 0.01 and the claim ρ = 0.

Question 38

Given a sample with r = 0.321, n = 30, and ? $\alpha$ = 0.10, determine the critical values $\mathrm { t } _ { 0 }$ necessary to test the claim $Q$ ? = 0.

A) $\pm 1.701$
B) $\pm 1.311$
C) $\pm 2.462$
D) $\pm 0.683$

Question 39

The data below are the number of absences and the final grades of 9 randomly selected students from a statistics class. Calculate the correlation coefficient, r. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | } \text { Number of absences, } \mathrm { x } & 0 & 3 & 6 & 4 & 9 & 2 & 15 & 8 & 5 \\\hline \text { Final Grade, } \mathrm { y } & 93 & 81 & 75 & 77 & 66 & 87 & 50 & 71 & 77\end{array}$$

A)-0.991
B)-0.888
C)-0.918
D)-0.899

Question 40

Given a sample with r = -0.765, n = 22, and ? $\alpha$ = 0.02, determine the standardized test statistic t necessary to test the claim ? $\text { Q }$ = 0. Round answers to three decimal places.

A)-5.312
B)-4.392
C)-3.783
D)-2.653

Question 41

The data below are the number of absences and the final grades of 9 randomly selected students from a
statistics class. Test the significance of the correlation coefficient using α and the claim ρ

Question 42

The data below are the gestation periods, in months, of randomly selected animals and their corresponding life
spans, in years. Find the equation of the regression line for the given data. 40

Question 43

Find the equation of the regression line for the given data. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | c | } \mathrm { x } & - 5 & - 3 & 4 & 1 & - 1 & - 2 & 0 & 2 & 3 & - 4 \\\hline \mathrm { y } & - 10 & - 8 & 9 & 1 & - 2 & - 6 & - 1 & 3 & 6 & - 8\end{array}$$

A) $\hat { y }$ = 2.097x - 0.552
B) $\mathrm { y }$ = 0.522x - 2.097
C) $\hat { \mathrm { y } }$ = 2.097x + 0.552
D) $\hat { \mathrm { y } }$ = -0.552x + 2.097

Question 44

The data below are the gestation periods, in months, of randomly selected animals and their corresponding life
spans, in years. Test the significance of the correlation coefficient using α = 0.01 and the claim ρ 40

Question 45

A manager wishes to determine the relationship between the number of miles (in hundreds of miles)the
managerʹs sales representatives travel per month and the amount of sales (in thousands of dollars)per month.
Test the significance of the correlation coefficient using α = 0.01 and the claim ρ

Question 46

For the data below, test the significance of the correlation coefficient using α = 0.10 and the claim ρ

Question 47

For the data below, test the significance of the correlation coefficient using α = 0.01 and the claim ρ

Question 48

Find the equation of the regression line for the given data. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | c } \mathrm { x } & - 5 & - 3 & 4 & 1 & - 1 & - 2 & 0 & 2 & 3 & - 4 \\\hline \mathrm { y } & 11 & - 6 & 8 & - 3 & - 2 & 1 & 5 & - 5 & 6 & 7\end{array}$$

A) $\hat{\mathrm { y }}$ = -0.206x + 2.097
B) $\hat { y }$ = 2.097x - 0.206
C) $\hat { \mathrm { y } }$ = 0.206x - 2.097
D) $\hat { \mathrm { y } }$ = -2.097x + 0.206

Question 49

Calculate the coefficient of correlation, r, letting Row 1 represent the x-values and Row 2 represent the
y-values. Now calculate the coefficient of correlation, r, letting Row 2 represent the x-values and Row 1
represent the y-values. What effect does switching the explanatory and response variables have on the
correlation coefficient?

Question 50

If Data A has a correlation coefficient of r = -0.991, and Data B has a correlation coefficient of r = 0.991, which correlation is correct?

A)Data A and Data B have the same strength in linear correlation.
B)Data A has a stronger linear correlation than Data B.
C)Data A has a weaker linear correlation than Data B.

Question 51

In order for applicants to work for the foreign-service department, they must take a test in the language of the
country where they plan to work. The data below shows the relationship between the number of years that
applicants have studied a particular language and the grades they received on the proficiency exam. Test the
significance of the correlation coefficient using α = 0.10 and the claim ρ

Question 52

The data below are the final exam scores of 10 randomly selected statistics students and the number of hours they studied for the exam. Find the equation of the regression line for the given data. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | c | } \text { Hours, } \mathrm { x } & 3 & 5 & 2 & 8 & 2 & 4 & 4 & 5 & 6 & 3 \\\hline \text { Scores, } \mathrm { y } & 65 & 80 & 60 & 88 & 66 & 78 & 85 & 90 & 90 & 71\end{array}$$

A) $\hat{y}$ = 5.044x + 56.113
B) $\hat { \mathrm { y } }$ = 56.113x - 5.044
C) $\hat { \mathrm { y } }$ = -56.113x - 5.044
D) $\hat { \mathrm { y } }$ = -5.044x + 56.113

Question 53

The data below are the temperatures on randomly chosen days during a summer class and the number of
absences on those days. Test the significance of the correlation coefficient using α = 0.02, and the claim ρ

Question 54

Explain the difference between ∑

Question 55

The data below are the final exam scores of 10 randomly selected statistics students and the number of hours
they studied for the exam. Test the significance of the correlation coefficient using α and the claim ρ

Question 56

Find the equation of the regression line for the given data. $$\begin{array} { c | c | c | c | c | c | c | c | c | c | c | } \mathrm { x } & - 5 & - 3 & 4 & 1 & - 1 & - 2 & 0 & 2 & 3 & - 4 \\\hline \mathrm { y } & 11 & 6 & - 6 & - 1 & 3 & 4 & 1 & - 4 & - 5 & 8\end{array}$$

A) $\hat { \mathrm { y } }$ = -1.885x + 0.758
B) $\hat { \mathrm { y } }$ = 0.758x + 1.885
C) $\text { y }$ = -0.758x - 1.885
D) $\hat { y }$ = 1.885x - 0.758

Question 57

In an area of the Midwest, records were kept on the relationship between the rainfall (in inches)and the yield
of wheat (bushels per acre). Test the significance of the correlation coefficient using α = 0.01 and the claim ρ

Question 58

The data below are the ages and systolic blood pressures (measured in millimeters of mercury)of 9 randomly
selected adults. Test the significance of the correlation coefficient using α = 0.05 and the claim ρ

Question 59

Which of the following values could not represent a correlation coefficient?

A)1.032
B)0
C)0.927
D)-1

Question 60

The data below are the average monthly temperatures, in and the monthly natural gas consumption, in ccf,
for a household in northwestern Pennsylvania. Test the significance of the correlation coefficient using α and the claim ρ

Question 61

The data below are the average monthly temperatures, in and the monthly natural gas consumption, in ccf,
for a household in northwestern Pennsylvania. Find the equation of the regression line for the given data.

Question 62

The data below are the gestation periods, in months, of randomly selected animals and their corresponding life
spans, in years. Use the regression equation to predict the life span, y, for a gestation period of 6 months, x.
Assume the variables x and y have a significant correlation.

Question 63

In order for applicants to work for the foreign-service department, they must take a test in the language of the country where they plan to work. The data below shows the relationship between the number of years that
Applicants have studied a particular language and the grades they received on the proficiency exam. Find the
Equation of the regression line for the given data. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | } \text { Number of years, } \mathrm { x } & 3 & 4 & 4 & 5 & 3 & 6 & 2 & 7 & 3 \\\hline \text { Grades on test, } \mathrm { y } & 61 & 68 & 75 & 82 & 73 & 90 & 58 & 93 & 72\end{array}$$

A) $\hat { \hat { y } }$ = 6.910x + 46.261
B) $\hat { \mathrm { y } }$ = 6.910x - 46.261
C) $\hat { \mathrm { y } }$ = 46.261x - 6.910
D) $\hat { \mathbf { y } }$ = 46.261x + 6.910

Question 64

Given the equation of a regression line is y = -2.5x+ 5.3, what is the best predicted value for y given x = 4.9? Assume that the variables x and y have a significant correlation.

A)-6.95
B)-17.55
C)17.55
D)6.95

Question 65

In an area of the Midwest, records were kept on the relationship between the rainfall (in inches)and the yield of wheat (bushels per acre). Find the equation of the regression line for the given data. $$\begin{array} { l | l | l | l | l | l | l | l | l | l } \text { Rain fall (in inches), } \mathrm { x } & 10.5 & 8.8 & 13.4 & 12.5 & 18.8 & 10.3 & 7.0 & 15.6 & 16.0 \\\hline \text { Yield (bushels per acre), y } & 50.5 & 46.2 & 58.8 & 59.0 & 82.4 & 49.2 & 31.9 & 76.0 & 78.8\end{array}$$

A) $\hat { \mathrm { y } }$ = 4.379x + 4.267
B) $\hat { \mathrm { y } }$ = -4.379x + 4.267
C) $\hat{\mathrm { y }}$ = 4.267x + 4.379
D) $\hat { \mathrm { y } }$ = 4.267x - 4.379

Question 66

In order for applicants to work for the foreign-service department, they must take a test in the language of the country where they plan to work. The data below show the relationship between the number of years that
Applicants have studied a particular language and the grades they received on the proficiency exam. What is
The best predicted value for y given x = 5.5? Assume that the variables x and y have a significant correlation. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | } \text { Number of years, } \mathrm { x } & 3 & 4 & 4 & 5 & 3 & 6 & 2 & 7 & 3 \\\hline \text { Grades on test, } \mathrm { y } & 61 & 68 & 75 & 82 & 73 & 90 & 58 & 93 & 72\end{array}$$

A)84
B)82
C)80
D)86

Question 67

Use the regression equation to predict the value of y for x = -2.8. Assume that the variables x and y have a significant correlation. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | c | } \mathrm { x } & - 5 & - 3 & 4 & 1 & - 1 & - 2 & 0 & 2 & 3 & - 4 \\\hline \mathrm { y } & - 10 & - 8 & 9 & 1 & - 2 & - 6 & - 1 & 3 & 6 & - 8\end{array}$$

A)-6.424
B)-5.320
C)3.643
D)0.551

Question 68

The data below are the number of absences and the final grades of 9 randomly selected students from a statistics class. Find the equation of the regression line for the given data. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | } \text { Number of absences, } \mathrm { x } & 0 & 3 & 6 & 4 & 9 & 2 & 15 & 8 & 5 \\\hline \text { Final grade, } \mathrm { y } & 98 & 86 & 80 & 82 & 71 & 92 & 55 & 76 & 82\end{array}$$

A) $\hat {\mathrm { y }}$

= -2.755x + 96.139
B) $\hat { y }$ = 96.139x - 2.755
C) $\hat { \mathrm { y } }$ = -2.755x - 96.139
D) $\mathrm { y }$ = -96.139x + 2.755

Question 69

The data below are the temperatures on randomly chosen days during a summer class and the number of absences on those days. Find the equation of the regression line for the given data. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | } \text { Temperature, } \mathrm { x } & 72 & 85 & 91 & 90 & 88 & 98 & 75 & 100 & 80 \\\hline \text { Number of absences, } \mathrm { y } & 3 & 7 & 10 & 10 & 8 & 15 & 4 & 15 & 5\end{array}$$

A) $\hat { \mathrm { y } }$ = 0.449x - 30.27
B) $\hat { y }$ = 30.27x - 0.449
C) $\hat { \mathrm { y } }$ = 0.449x + 30.27
D) $\hat { y }$ = 30.27x + 0.449

Question 70

Given the equation of a regression line is y = 3.5x - 5.4, what is the best predicted value for y given x = -1.2? Assume that the variables x and y have a significant correlation.

A)-9.6
B)12.3
C)-6.9
D)-12.3

Question 71

The data below are the average monthly temperatures, in and the monthly natural gas consumption, in ccf,
for a household in northwestern Pennsylvania. What is the best-predicted value for the gas consumption, y,
given x = 50°F? Assume that the variables x and y have a significant correlation.

Question 72

The data below are the number of absences and the final grades of 9 randomly selected students from a statistics class. What is the best predicted value for y given x = 10? Assume that the variables x and y have a
Significant correlation. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | } \text { Number of absences, } x & 0 & 3 & 6 & 4 & 9 & 2 & 15 & 8 & 5 \\\hline \text { Final grade, } y & 98 & 86 & 80 & 82 & 71 & 92 & 55 & 76 & 82\end{array}$$

A)69
B)70
C)71
D)68

Question 73

The data below are ages and systolic blood pressures (measured in millimeters of mercury)of 9 randomly selected adults. Find the equation of the regression line for the given data. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | } \text { Age, } \mathrm { x } & 38 & 41 & 45 & 48 & 51 & 53 & 57 & 61 & 65 \\\hline \text { Pressure, } \mathrm { y } & 116 & 120 & 123 & 131 & 142 & 145 & 148 & 150 & 152\end{array}$$

A) $\hat { y }$ = 1.488x + 60.461
B) $\hat { y }$ = 60.461x - 1.488
C) $\hat { y }$ = 1.448x - 60.461
D) $\hat { \mathrm { y } }$ = 60.461x + 1.488

Question 74

In an area of the Midwest, records were kept on the relationship between the rainfall (in inches)and the yield of wheat (bushels per acre). Which is the best predicted value for y given x = 7.3? Assume that the variables x
And y have a significant correlation. $$\begin{array} { l | l | l | l | l | l | l | l | l | l } \text { Rain fall (in inches), x } & 10.5 & 8.8 & 13.4 & 12.5 & 18.8 & 10.3 & 7.0 & 15.6 & 16.0 \\\hline \text { Yield (bushels per acre), y } & 50.5 & 46.2 & 58.8 & 59.0 & 82.4 & 49.2 & 31.9 & 76.0 & 78.8\end{array}$$

A)36.2
B)36.5
C)36.0
D)36.7

Question 75

A manager wishes to determine the relationship between the number of miles (in hundreds of miles)the manager?s sales representatives travel per month and the amount of sales (in thousands of dollars)per month.
Find the equation of the regression line for the given data. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | } \text { Miles traveled, } \mathrm { x } & 2 & 3 & 10 & 7 & 8 & 15 & 3 & 1 & 11 \\\hline \text { Sales, } \mathrm { y } & 31 & 33 & 78 & 62 & 65 & 61 & 48 & 55 & 120\end{array}$$

A) $\hat{y}$ = 3.529x + 37.916
B) $\hat { \mathrm { y } }$ = 37.916x - 3.529
C) $\hat { \mathrm { y } }$ = 3.529x - 37.916
D) $\hat { y }$ = 37.916x + 3.529

Question 76

The data below are the temperatures on randomly chosen days during a summer class and the number of absences on those days. What is the best predicted value for y given x = 84? Assume that the variables x and y
Have a significant correlation. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | } \text { Temperature, } \mathrm { x } & 72 & 85 & 91 & 90 & 88 & 98 & 75 & 100 & 80 \\\hline \text { Number of absences, } \mathrm { y } & 3 & 7 & 10 & 10 & 8 & 15 & 4 & 15 & 5\end{array}$$

A)7
B)8
C)9
D)10

Question 77

The data below are the ages and systolic blood pressures (measured in millimeters of mercury)of 9 randomly selected adults. What is the best predicted value for y given x = 41? Assume that the variables x and y have a
Significant correlation. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | } \text { Age, } \mathrm { x } & 38 & 41 & 45 & 48 & 51 & 53 & 57 & 61 & 65 \\\hline \text { Pressure, } \mathrm { y } & 116 & 120 & 123 & 131 & 142 & 145 & 148 & 150 & 152\end{array}$$

A)121
B)123
C)119
D)117

Question 78

Use the regression equation to predict the value of y for x = -0.2. Assume that the variables x and y have a significant correlation. $$\begin{array} { c | c | c | c | c | c | c | c | c | c | c | } \mathrm { x } & - 5 & - 3 & 4 & 1 & - 1 & - 2 & 0 & 2 & 3 & - 4 \\\hline \mathrm { y } & 11 & 6 & - 6 & - 1 & 3 & 4 & 1 & - 4 & - 5 & 8\end{array}$$

A)1.135
B)0.381
C)-2.037
D)1.733

Question 79

Given the equation of a regression line is y = 3x - 1, what is the best predicted value for y given x = 4? Assume that the variables x and y have a significant correlation.

A)11
B)13
C)1
D)6

Question 80

The data below are the final exam scores of 10 randomly selected statistics students and the number of hours they studied for the exam. What is the best predicted value for y given x = 3? Assume that the variables x and y
Have a significant correlation. $$\begin{array} { l | c | c | c | c | c | c | c | c | c | c | } \text { Hours, } \mathrm { x } & 3 & 5 & 2 & 8 & 2 & 4 & 4 & 5 & 6 & 3 \\\hline \text { Scores, y } & 65 & 80 & 60 & 88 & 66 & 78 & 85 & 90 & 90 & 71\end{array}$$

A)71
B)70
C)69
D)72