Question 1

To get the best deal on a microwave oven, Amanda called six appliance stores and asked the cost and volume of several models. The prices and volumes she was quoted are listed below. Amanda later learned that the group of 3 microwaves with volumes greater than 1 cubic foot and costing less than $200 were discontinued models Priced lower than normal. How does this change your view of the correlation? $$\begin{array} { c c } 
\hline \text { Volume (cu.ft) } & \text { Price } ( \$ ) \
\hline 1.5 & 17 \
0.7 & 49 \
1.5 & 349 \
1.9 & 183 \
0.5 & 119 \
2.2 & 119 \
1.8 & 417 \
1.5 & 463 \
1 & 200 \
\hline
\end{array}$$

Accepted Answer

A)  Within each of the two groups, the correlation is less than it is overall.
B)  The group of discontinued models has a stronger correlation than the other group.
C)  There is little correlation either within the groups or overall.
D)  Within each of the two groups, the correlation is stronger than it is overall.  D

Question 2

Select the best-fit line for the data on the scatter diagram. If none of the lines fit the data, write "none of the lines".
-Select the best-fit line on the scatter diagram below.

Accepted Answer

A)    C\mathrm { C }C 
B)   B
C)    A\mathrm { A }A 
D)   none of the lines  D

Question 3

To get the best deal on a microwave oven, Amanda called six appliance stores and asked the cost and volume of several models. The prices and volumes she was quoted are listed below. Estimate or compute the correlation
Coefficient. $$\begin{array} { c c } 
\hline \text { Volume (cu.ft) } & \text { Price } ( \$ ) \
\hline 0.5 & 119 \
2.2 & 119 \
1.8 & 417 \
1.5 & 463 \
1 & 200 \
1.5 & 17 \
0.7 & 49 \
1.5 & 349 \
1.9 & 183 \
\hline
\end{array}$$

Accepted Answer

A)  -0.3
B)  0.3
C)  -0.7
D)  0.7  B

Question 4

Solve the problem.
-The following table gives the total sales (revenue)and profits for 8 retailers. Construct a scatter diagram for thedata and state whether sales and profits for these companies have no correlation, a positive correlation, or a
Negative correlation.

$\begin{array}{l}
\begin{array} { l c c } 
\hline \text { Company } & \begin{array} { c } 
\text { Total Sales } \
\text { (Millions of \$) }
\end{array} & \begin{array} { c } 
\text { Profits } \
\text { (Millions of \$) }
\end{array} \
\hline \text { Adams } & 9.5 & 0.5 \
\text { Browns } & 22.0 & 1.4 \
\text { Clay } & 35.0 & 1.8 \
\text { Donners } & 64.0 & 3.0 \
\text { Esters } & 27.5 & 0.9 \
\text { Framer } & 45.0 & 2.6 \
\text { Gillies } & 15.0 & 0.8 \
\text { Hays } & 57.0 & 2.2 \
\hline
\end{array}\
\end{array}$

Accepted Answer

A)   Positive correlation
B)   Negative correlation
C)   Positive correlation
D)   No correlation

Question 5

State whether there is no correlation, a positive correlation, or a negative correlation between the x and y variables. If there is a correlation, state whether it is most likely due to coincidence, a common underlying cause, or a direct cause.
- For a group of employees at the local video store, the scatter diagram compares the number of days worked per year (y)and the average number of miles walkedweekly (x).

Accepted Answer

A)  Positive correlation; coincidence
B)  No correlation
C)  Positive correlation; direct cause
D)  Positive correlation; common underlying cause

Question 6

Select the best estimate of the correlation coefficient for the data depicted in the scatter diagram.
-

Accepted Answer

A)  -0.1
B)  -0.9
C)  -0.5
D)  0.9

Question 7

Solve the problem.
-The table below shows the times (in hours)that seven students spend watching television and using the internet. Construct a scatter diagram for the data and state whether these times have no correlation, a positive correlation, or a negative correlation.

$\begin{array}{l}
\text { Student TV TimeInternet Time }\
\begin{array}{lcc} 
& \text { (hours) } & \text { (hours) } \
\text { Tom } & 9 & 6 \
\text { Dick } & 5 & 4 \
\text { Harry } & 3 & 0 \
\text { Sue } & 8 & 9 \
\text { Betty } & 8 & 10 \
\text { Erin } & 6 & 1 \
\text { Jan } & 7 & 10
\end{array}
\end{array}$

Accepted Answer

A)   Negative correlation
B)   Positive correlation
C)   No correlation
D)   Positive correlation

Question 8

State whether you believe the two variables are correlated. If you believe they are correlated, state whether the correlation is positive or negative.
-Rate of pedaling a bicycle and speed of the bicycle

Accepted Answer

A)  Positive correlation
B)  Negative correlation
C)  Not correlated

Question 9

Select the best-fit line for the data on the scatter diagram. If none of the lines fit the data, write "none of the lines".
-Select the best-fit line on the scatter diagram below.

Accepted Answer

A)    A\mathrm { A }A 
B)    CCC 
C)    B\mathrm { B }B 
D)   none of the lines

Question 10

Select the best estimate of the correlation coefficient for the data depicted in the scatter diagram.
-

Accepted Answer

A)  -0.65
B)  0.95
C)  0.65
D)  0.20

Question 11

The table contains the weights (in pounds)and heights (in inches)of 9 randomly selected adults. Construct a scatter diagram for the data.

$$\begin{array}{l}
\begin{array} { c c } 
\hline \text { Weight (lb)}&\text { Height (in.) }  \ 
\hline 125 & 60 \
130 & 62 \
128 & 70 \
130 & 65 \
155 & 75 \
150 & 72 \
135 & 68 \
145 & 68 \
145 & 65 \
\hline
\end{array}\
\end{array}$$

Accepted Answer

The answer of The table contains the weights (in pounds)and...

Question 12

Solve the problem.
-The table below shows the sales and profits of a company from 2000 to 2005. Construct a scatter diagram for the data and state whether sales and profits for this company have no correlation, a positive correlation, or a negative correlation for this period.

$\begin{array} { c c c } 
\text { Year } & \text { (Millions of \$) } & \begin{array} { c } 
\text { Profits } \
\text { (Millions of \$) }
\end{array} \
2000 & 7 & 1 \
2001 & 12 & 4 \
2002 & 10 & 2 \
2003 & 9 & 2 \
2004 & 13 & 3 \
2005 & 8 & 0
\end{array}$

Accepted Answer

A)   Negative correlation
B)   Positive correlation
C)   No correlation
D)   No correlation

Question 13

Provide an appropriate response.
-Estimate the coordinates of the outlier on the graph.

Accepted Answer

A)    (17,9) ( 17,9 ) (17,9)  
B)    (4,17) ( 4,17 ) (4,17)  
C)    (9,17) ( 9,17 ) (9,17)  
D)    (17,4) ( 17,4 ) (17,4)

Question 14

State whether there is no correlation, a positive correlation, or a negative correlation between the x and y variables. If there is a correlation, state whether it is most likely due to coincidence, a common underlying cause, or a direct cause.
- For several customers at the local bookstore, the scatter diagram compares the weight of their books (y)and the umber of pages in them(x).

Accepted Answer

A)  Positive correlation; coincidence
B)  Positive correlation; direct cause
C)  No correlation
D)  Negative correlation; common underlying cause

Question 15

State whether there is no correlation, a positive correlation, or a negative correlation between the x and y variables. If there is a correlation, state whether it is most likely due to coincidence, a common underlying cause, or a direct cause.
- For a group of students in a statistics class, the scatter diagram compares their test scores (y)and the amount of loose pocket change they have(x).

Accepted Answer

A)  Negative correlation; direct cause
B)  Negative correlation; coincidence
C)  No correlation
D)  Negative correlation; common underlying cause

Question 16

Construct a scatter diagram with several groups of data such that there is no correlation of data within the groups and no correlation among all the data.

Accepted Answer

A)  
B)  
C)  
D)

Question 17

Construct a scatter diagram with two groups of data that have no correlation within either group but shows a moderate correlation among all the data.

Accepted Answer

A)  
B)  
C)  
D)

Question 18

Solve the problem.
-A study found a strong correlation between excessive red meat consumption and cholesterol problems . If excessive red meat consumption causes cholesterol problems , how could some of the people in the study frequently eat red meat and yet show no signs of cholesterol problems ?

Accepted Answer

The answer of Solve the problem.
-A study found a strong...

Question 19

Answer the question using the value of r and the given best-fit line on the scatter diagram.
- The scatter diagram and best-fit line show the data for the price of a stock (y)and U.S. employment (x). The correlation coefficient r is 0.8. Predict the stock price for an employment value of 5.

Accepted Answer

A)  5.9
B)  4.9
C)  7
D)  No valid prediction is possible.

Question 20

Solve the problem.
-A local highway has an express lane that contains no exits and runs parallel to the other lanes for five miles before merging back with them. A study found that during rush hour traffic, driving times in the express lane were strongly correlated with the longest travel times over the five mile stretch in question. One driver commented that the express lane causes traffic slowdowns and was a waste of money. Comment on how persuasive this comment is and how additional research could help.

Accepted Answer

The answer of Solve the problem.
-A local highway has an...

Exam 7: Correlation and Causality

Select the best estimate of the correlation coefficient for the data depicted in the scatter diagram. -

State whether you believe the two variables are correlated. If you believe they are correlated, state whether the correlation is positive or negative. -Rate of pedaling a bicycle and speed of the bicycle

Select the best estimate of the correlation coefficient for the data depicted in the scatter diagram. -

Provide an appropriate response. -Estimate the coordinates of the outlier on the graph.

Construct a scatter diagram with several groups of data such that there is no correlation of data within the groups and no correlation among all the data.

Construct a scatter diagram with two groups of data that have no correlation within either group but shows a moderate correlation among all the data.

Solve the problem. -A study found a strong correlation between excessive red meat consumption and cholesterol problems . If excessive red meat consumption causes cholesterol problems , how could some of the people in the study frequently eat red meat and yet show no signs of cholesterol problems ?

Answer the question using the value of r and the given best-fit line on the scatter diagram. - The scatter diagram and best-fit line show the data for the price of a stock (y) and U.S. employment (x) . The correlation coefficient r is 0.8. Predict the stock price for an employment value of 5.

Exam 7: Correlation and Causality

Select the best-fit line for the data on the scatter diagram. If none of the lines fit the data, write "none of the lines". -Select the best-fit line on the scatter diagram below.

Select the best estimate of the correlation coefficient for the data depicted in the scatter diagram. -

State whether you believe the two variables are correlated. If you believe they are correlated, state whether the correlation is positive or negative. -Rate of pedaling a bicycle and speed of the bicycle

Select the best-fit line for the data on the scatter diagram. If none of the lines fit the data, write "none of the lines". -Select the best-fit line on the scatter diagram below.

Select the best estimate of the correlation coefficient for the data depicted in the scatter diagram. -

Provide an appropriate response. -Estimate the coordinates of the outlier on the graph.

Construct a scatter diagram with several groups of data such that there is no correlation of data within the groups and no correlation among all the data.

Construct a scatter diagram with two groups of data that have no correlation within either group but shows a moderate correlation among all the data.

Solve the problem. -A study found a strong correlation between excessive red meat consumption and cholesterol problems . If excessive red meat consumption causes cholesterol problems , how could some of the people in the study frequently eat red meat and yet show no signs of cholesterol problems ?

Answer the question using the value of r and the given best-fit line on the scatter diagram. - The scatter diagram and best-fit line show the data for the price of a stock (y) and U.S. employment (x) . The correlation coefficient r is 0.8. Predict the stock price for an employment value of 5.