Consider the data in Table P-3 where X = weekly advertising expenditures and Y = weekly sales.

a. Does a significant relationship exist between advertising expenditures and sales?
b. State the prediction equation.
c. Forecast sales for an advertising expenditure of $50.
d. What percentage of the variation in sales can be explained with the prediction equation?
e. State the amount of unexplained variation.
f. State the amount of total variation.

TABLE P-3 Y (S) X (S) Y (S) X (S) 1,250 1.380 1.425 1.425 1,450 41 54 63 54 48 1,300 1,400 1,510 1,575 1,650 46 62 61 64 71