Question

1. For the data given below find the forecast for year 10 using
   1. Comparing the weighted average and moving average methods in b and c which method yields better results based on MAD?
   2. Use regression analysis to find the forecast for year 10.

Period	Actual	Forecast
1	13
2	25
3	35
4	46
5	66
6	71
7	80
8	88
9	95
10	?

Answer 1

PERIOD (X)	DEMAND (Y)	X	Y	X * Y	X^2
1	13	1	13	13	1
2	25	2	25	50	4
3	35	3	35	105	9
4	46	4	46	184	16
5	66	5	66	330	25
6	71	6	71	426	36
7	80	7	80	560	49
8	88	8	88	704	64
9	95	9	95	855	81
SIGMA		45	519	3227	285

INTERCEPT = (SIGMA(Y) * SIGMA(X^2) - SIGMA(X) * SIGMA(XY)) / (N * SIGMA(X^2) - SIGMA(X)^2)

INTERCEPT = (519 * 285) - (45 * 3227) / ((9 * 285) - 45^2) = 5

SLOPE = ((N * SIGMA(XY)) - (SIGMA(X) * SIGMA(Y))) - (N * SIGMA(X^2) - SIGMA(X)^2)

SLOPE = ((9 * 3227) - (45 * 519) / ((9 * 285) - 45^2) = 10.533

Y = A + B(X), WHERE A IS THE INTERCEPT, B IS THE SLOPE, X IS THE PERIOD = 5 + (10.533 * X)

FOR THE VALUE OF X = 10 FORECAST = 5 + (10.533 * 10) = 110.33

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