Question

Consider the following time series data.

Week	1	2	3	4	5	6
Value	19	14	17	12	18	15

Using the average of all the historical data as a forecast for the next period, compute the following measures of forecast accuracy.

Round your answers to two decimal places.

a. Mean absolute error.

b. Mean squared error.

c. Mean absolute percentage error.

d. What is the forecast for week ?

Answer 1

Time period	Actual Value(A)	historical Data Forecast(F)	Forecast error E=|A-F|	Squared Forecast Error	|A-F|A
1	19
2	14	19.00	5.00	25.00	0.36
3	17	16.50	0.50	0.25	0.03
4	12	16.67	4.67	21.78	0.39
5	18	15.50	2.50	6.25	0.14
6	15	16.00	1.00	1.00	0.07
7		15.83
		Total	13.666667	54.27777778	0.98
		Average	2.73	10.86	19.62%
			MAD	MSE	MAPE

a)

Mean absolute error =2.73 (please try 2.7 if one decimal place is required)

b. Mean squared error =10.86 (please try 10.9  if one decimal place is required)

c. Mean absolute percentage error.=19.62 %  (please try 19.6 if one decimal place is required)

d. What is the forecast for week =15.83  (please try 15.8 if one decimal place is required)