1.The quarterly sales data (number of copies sold) for Moraga Bookstore over the past three years follow.

Year

Quarter 1

Quarter 2

Quarter 3

Quarter 4

1

16

25

22

15

2

19

31

25

18

3

21

33

27

17

a.Construct a time-series plot. What type of pattern(s) exists in the data?

b.Compute the seasonal index for the four quarters.

c.Compute the linear trend equation for the deseasonalized data.

d. Calculate the unadjusted sales forecast for Quarter 1 of year 4.

e.Calculate the seasonally adjusted sales forecast for Quarter 1 of year 4.