Q8. The following data represent a company's yearly sales volume and its advertising expenditure over a period of 8 years.

Sales in

Millions of Dollars

Advertising

in ($10,000)

15

32

16

33

18

35

17

34

16

36

19

37

19

39

24

42

a.Develop a scatter diagram of sales versus advertising and explain what it shows regarding the relationship between sales and advertising.(2)

b.Obtain the coefficient of correlation. Interpret the value.(2)

c.Provide the regression equation to predict sales on the basis advertising expenditure.(2)

d.What does the slope of the estimated regression line indicate?(1)

e.Find the value of coefficient of determination and write its interpretation.(2)

f.If the company's advertising expenditure is $400,000 what are the predicted sales? Give the answer in dollars(2)

g.Develop a 95% confidence interval estimate for the slope and interpret its meaning.(2)