A manager of a local retail store analyzes the relationship between advertising and sales by reviewing the store’s data for the previous six months.

Advertising (in $100s) ....Sales (in $1,000s)

20 ............15

25 ............18

30 ............20

22 ............16

27 ............19

26 ............20

a. Calculate the mean of advertising and the mean of sales.

b. Calculate the standard deviation of advertising and the standard deviation of sales.

c. Calculate and interpret the covariance between advertising and sales.

d. Calculate and interpret the correlation coefficient.