A Toyota car dealer has been running 1-minute commercials (ads) on a local TV station for ten weeks. He has kept a weekly record of the number of TV ads and the number of cars sold. His records show the following.

#ofads 6 20 0 14 25 16 28 18 10 8 # of cars sold 15 31 10 16 28 20 40 25 12 15 The least squares regression line for this data is y = 6.56 + 1.01x

a) Draw a scatter plot of the data. (7 pts)

b) Based on your scatter plot, is the correlation between the number of ads and cars sold positive or negative?

Explain. (2 pts)

c) Using the equation, how many cars can the dealer expect to sell if 12 ads per week are shown on TV? (3 pts)

d) There is a correlation coefficient (r) of .919 between the number of ads and the number of cars sold in a week. What percent of the variation in the number of cars sold can be accounted for by the number of advertisements shown? (3 pts)