Question

1. A popular brand of skate board has had the following sales history for the past 36 periods. Sales 737 598 495 609 701 755 691 581 632 744 816 710 Period Sales Period Sales Period 13 525 595 694 523 574 610 679 726 573 503 618 696 25 26 27 28 29 30 31 32 515 431 533 612 658 562 522 575 650 680 490 498 15 16 17 18 19 20 4 34 35 36 10 23 24 12 a. Use the first 36 past sales data to initialize a Winter's Multiplicative Seasonal forecasting model. Use linear regression (regression line fitted using all 36 periods) to initialize your model.

Answer 1

Regression Analysis
	r²	0.320	n	36
	r	0.566	k	1
	Std. Error	76.461	Dep. Var.	S
ANOVA table
Source	SS	df	MS	F	p-value
Regression	93,563.2665	1	93,563.2665	16.00	.0003
Residual	198,772.3724	34	5,846.2462
Total	292,335.6389	35
Regression output					confidence interval
variables	coefficients	std. error	t (df=34)	p-value	95% lower	95% upper	std. coeff.
Intercept	523.4063						0.000
t	4.9075	1.2267	4.000	.0003	2.4145	7.4004	0.566

The regression equation is Sales = 523.4063 + 4.9075 Period