Problem: I am trying to develop a model using Excel (data table perhaps) that can be used to forecast monthly sales on a month-by-month basis based on previous monthly data starting with January of year 7. The sales history is given below:
|
Year
|
Jan
|
Feb
|
Mar
|
Apr
|
May
|
Jun
|
Jul
|
Aug
|
Sep
|
Oct
|
Nov
|
Dec
|
|
1
|
1124
|
1052
|
1070
|
1049
|
1087
|
1117
|
1113
|
1144
|
1159
|
1169
|
1162
|
1191
|
|
2
|
1173
|
1218
|
1261
|
1267
|
1277
|
1287
|
1313
|
1309
|
1308
|
1341
|
1379
|
1379
|
|
3
|
1413
|
1455
|
1426
|
1457
|
1428
|
1424
|
1414
|
1422
|
1422
|
1442
|
1438
|
1432
|
|
4
|
1400
|
1414
|
1416
|
1433
|
1507
|
1483
|
1509
|
1520
|
1593
|
1592
|
1546
|
1600
|
|
5
|
1593
|
1559
|
1591
|
1669
|
1676
|
1753
|
1763
|
1798
|
1785
|
1849
|
1898
|
1912
|
|
6
|
1931
|
1917
|
1940
|
1948
|
1923
|
1951
|
2003
|
2029
|
2102
|
2106
|
2099
|
2119
|
|
7
|
|
|
|
|
|
|
|
|
|
|
|
|