The data in the table below are for retail sales in book stores by quarter. (c3p13)

U.S. Retail Book Sales (in Millions of Dollars, NSA)

Date	Sales
Mar-02	1,866
Jun-02	1,666
Sep-02	2,351
Dec-02	2,455
Mar-03	2,169
Jun-03	1,815
Sep-03	2,498
Dec-03	2,637
Mar-04	2,326
Jun-04	2,020
Sep-04	2,858
Dec-04	2,915
Mar-05	2,725
Jun-05	2,283
Sep-05	3,134
Dec-05	3,066
Mar-06	2,876
Jun-06	2,445
Sep-06	3,190
Dec-06	3,407
Mar-07	3,197
Jun-07	2,575
Sep-07	3,290
Dec-07	3,693
Mar-08	3,273
Jun-08	2,713
Sep-08	3,514
Dec-08	3,794
Mar-09	3,480
Jun-09	2,943
Sep-09	3,654
Dec-09	4,108
Mar-10	3,628
Jun-10	3,203
Sep-10	4,051
Dec-10	4,010
Mar-11	3,719
Jun-11	3,084
Sep-11	4,234
Dec-11	4,073
Mar-12	3,983
Jun-12	3,132
Sep-12	4,328
Dec-12	4,007
Mar-13	3,969
Jun-13	3,257
Sep-13	4,824
Dec-13	4,129
Mar-14	4,298
Jun-14	3,312
Sep-14	4,811
Dec-14	4,336
Mar-15	4,261
Jun-15	3,278
Sep-15	4,991
Dec-15	4,447

a. Plot these data and examine the plot. Does this view of the data suggest a particular smoothing model? Do the data appear to be seasonal? Explain.

b. Use an exponential smoothing method to forecast the next four quarters. Plot the actual and forecast values.

How do i do this in excel?