In: Math
he following data are for calculator sales in units at an electronics store over the past nine weeks:
|
Week |
Sales |
Week |
Sales |
|
1 |
4444 |
6 |
5757 |
|
2 |
4545 |
7 |
6565 |
|
3 |
4646 |
8 |
5555 |
|
4 |
5151 |
9 |
6464 |
|
5 |
5757 |
Use trend projection with regression to forecast sales for weeks
10minus−13.
What are the error measures (CFE, MSE,
sigmaσ,
MAD, and MAPE) for this forecasting procedure? How about
r squaredr2?
Obtain the trend projection with regression forecast for weeks
10minus−13.
(Enter your responses rounded to two decimal places.)
|
Period |
Forecast, Bold Upper F Subscript tFt |
|
10 |
nothing |
|
11 |
nothing |
|
12 |
nothing |
|
13 |
nothing |
Obtain the error measures.
CFE: MSE: sigmaσ: MAD: MAPE:
Find the coefficient of determination (R squared)
R squared =
Trend projection with regression to forecast sales for weeks =
| t | yt | tyt | t^2 |
| 1 | 4444 | 4444 | 1 |
| 2 | 4545 | 9090 | 4 |
| 3 | 4646 | 13938 | 9 |
| 4 | 5151 | 20604 | 16 |
| 5 | 5757 | 28785 | 25 |
| 6 | 5757 | 34542 | 36 |
| 7 | 6565 | 45955 | 49 |
| 8 | 5555 | 44440 | 64 |
| 9 | 6464 | 58176 | 81 |
| total=45 | 48884 | 259974 | 285 |


b1=259.233333

=5431.5555
=5
b0=5431.5555 - 259.233333*5
b0=4135.38884
Trend Equation=


T10=6727.72184

By substituting the values, we get,

T11=6986.95514

T12= 7246.18844

T13=7505.42174
By using minitab software ,
Trend Analysis for sales
Data sales
Length 9
NMissing 0
Fitted Trend Equation=
Yt = 4135 + 259.2×t
Accuracy Measures=
MAPE 4
MAD 235
MSD 111405