Question

Consider the following time series.

Period   Demand
1   6
2   7
3   5
4   9
5   13
6   16
7   12
8   16

​a) Using a trend​ projection, forecast the demand for Period 9.

​a) The forecasted demand for Period 9 is

​(Type an integer or decimal rounded to one decimal place as​ needed.)

​b) Calculate the MAD for this forecast.

​b) MAD=

​(Type an integer or decimal rounded to one decimal place as​ needed.)

Answer 1

a)

regression equation is y = 1.5714X+3.4286

for period 9

When x = 9

y = 1.5714(9) + 3.4286 = 17.571=17.6

b)

Observation	Y	Predicted	Error	Absolute error
1	6.0	5.0	1.0	1.0
2	7.0	6.6	0.4	0.4
3	5.0	8.1	-3.1	3.1
4	9.0	9.7	-0.7	0.7
5	13.0	11.3	1.7	1.7
6	16.0	12.9	3.1	3.1
7	12.0	14.4	-2.4	2.4
8	16.0	16.0	0.0	0.0
				sum = 12.6

MAD = 12.6/8 = 1.575 = 1.6