AP STATS Warm Up #8

A simple random sample of 25 world-ranked tennis players provides the following statistics.

Based on this data, what is the resulting linear regression equation?

• Predicted Winnings = 1,390,000 + 59,400 hours

• Predicted Winnings = 1,300,000 + 71,300 hours

• Predicted Winnings = -63,400 + 258,000 hours

• Predicted Winnings = -443,000 + 310,000 hours

• Predicted Winnings = -10,000,000 + 1,620,000 hours

• negative

• 0

• positive

• dependent on the value of r 

• the value cannot be determined

Suppose the correlation between two variables is r = 0.28. What will the new correlation be if 0.17 is added to all the values of the x-variable, every ​value of the y-variable is doubled, and the two variables are interchanged?

• 0.28

• 0.45

• 0.56 

• 0.90 

• -0.28

Data are obtained from a random sample of adult women with regards to their age and their monthly expenditures on health products. The resulting regression equation is given.

What percentage of the variation in health product expenditures can be explained by looking at age?

• 0.23%

• 23%

• 7.29%

• 27% 

• 52%

Which of the following are true statements about the correlation ​coefficient r?

A.) It is not affected by changes in the measurement units of variables.

B.) It is not affected by which variable is called x and which is called y.

C.) It is not affected by extreme or unusual values.

• A & B

• A & C

• B & C

• A, B & C