This sheet presents the quarterly sale of Samsung60 TVs at Best Buy San Marcos in the past 5 years
a) Make a time series plot. What type of pattern do you observe in the data?
b) Make seasonal forecasts using three dummy variables of Qtr1= 1 if quarter 1, 0 otherwise; Qtr2=1 if quarter 2,
0 otherwise; and Qtr3= 1 if quarter 3, 0 otherwise.
c) Make seasonal-trend forecasts using period factor and three dummy variables of Qtr1= 1 if quarter 1, 0 otherwise; Qtr2=1 if quarter 2, 0 otherwise; and Qtr3= 1 if quarter 3, 0 otherwise.
Historical sale in the past 5 years
Year	Quarter	Sale ($100K)
1	1	15
	2	21
	3	25
	4	19
2	1	19
	2	21
	3	35
	4	19
3	1	17
	2	27
	3	42
	4	20
4	1	19
	2	27
	3	38
	4	22
5	1	19
	2	26
	3	49
	4	26