Question

Carolina Roof Construction sells roofing supplies and equipment. Experience has shown the owner, John Fransen, that the sales have a significant seasonal variability. It is critical that the sales forecasts are accurate so Fransen can plan the cash flow of the business. The file Carolina Roof Construction Spring 2019 contains the sales figures for 2011 to 2018.  Produce a forecast using regression of deseasonalized sales and reseasonalize the forecast. Write a report to Frans and include your forecast for winter, spring, summer and fall sales for Carolina Roof Construction in 2019. Include in your report

a) the typical seasonal indexes for sales using the ratio-to-moving-average method,

b) the deseasonalized trend equation,

c) project sales for 2019 using the trend equation and seasonally adjust these values to find the predicted sales for each quarter.

Year	Quarter	Sales ($1,000)
2011	Winter	212
	Spring	182
	Summer	62
	Fall	241
2012	Winter	217
	Spring	217
	Summer	88
	Fall	233
2013	Winter	246
	Spring	229
	Summer	93
	Fall	282
2014	Winter	257
	Spring	252
	Summer	115
	Fall	294
2015	Winter	279
	Spring	266
	Summer	111
	Fall	304
2016	Winter	304
	Spring	291
	Summer	119
	Fall	310
2017	Winter	330
	Spring	296
	Summer	126
	Fall	327
2018	Winter	288
	Spring	276
	Summer	111
	Fall	334

Answer 1

Time	Year	Quarter	Y (Sales)	MA	CMA	Y/CMA	S (Seasonal Index)	Deseasonalized = Y/S	T (Trend)	F (Forcast) = S*T
1	2011	W	212				1.19	178.8	176	208.7
2		Sp	182				1.12	162.9	179.4	200.4
3		Su	62	174.3	174.9	0.35	0.45	138.1	182.7	82
4		F	241	175.5	179.9	1.34	1.25	193.4	186.1	231.9
5	2012	W	217	184.3	187.6	1.16	1.19	183	189.5	224.7
6		Sp	217	190.8	189.8	1.14	1.12	194.3	192.8	215.4
7		Su	88	188.8	192.4	0.46	0.45	196	196.2	88.1
8		F	233	196	197.5	1.18	1.25	187	199.6	248.7
9	2013	W	246	199	199.7	1.23	1.19	207.4	203	240.8
10		Sp	229	200.3	206.4	1.11	1.12	205	206.3	230.4
11		Su	93	212.5	213.9	0.43	0.45	207.1	209.7	94.2
12		F	282	215.3	218.2	1.29	1.25	226.3	213.1	265.5
13	2014	W	257	221	223.8	1.15	1.19	216.7	216.5	256.8
14		Sp	252	226.5	228	1.11	1.12	225.6	219.8	245.5
15		Su	115	229.5	232.3	0.5	0.45	256.1	223.2	100.2
16		F	294	235	236.8	1.24	1.25	236	226.6	282.3
17	2015	W	279	238.5	238	1.17	1.19	235.2	229.9	272.7
18		Sp	266	237.5	238.8	1.11	1.12	238.1	233.3	260.6
19		Su	111	240	243.2	0.46	0.45	247.2	236.7	106.3
20		F	304	246.3	249.4	1.22	1.25	244	240.1	299.2
21	2016	W	304	252.5	253.5	1.2	1.19	256.3	243.4	288.7
22		Sp	291	254.5	255.3	1.14	1.12	260.5	246.8	275.7
23		Su	119	256	259.3	0.46	0.45	265	250.2	112.3
24		F	310	262.5	263.2	1.18	1.25	248.8	253.6	316
25	2017	W	330	263.8	264.7	1.25	1.19	278.2	256.9	304.7
26		Sp	296	265.5	267.7	1.11	1.12	265	260.3	290.8
27		Su	126	269.8	264.6	0.48	0.45	280.6	263.7	118.4
28		F	327	259.3	256.8	1.27	1.25	262.4	267.1	332.8
29	2018	W	288	254.3	252.4	1.14	1.19	242.8	270.4	320.7
30		Sp	276	250.5	251.4	1.1	1.12	247.1	273.8	305.8
31		Su	111	252.3			0.45	247.2	277.2	124.5
32		F	334				1.25	268.1	280.5	349.5
33	2019	W					1.19		283.9	336.7
34		Sp					1.12		287.3	320.9
35		Su					0.45		290.7	130.5
36		F					1.25		294	366.3