Month | Sales (2005) | Sales (2006) |
Jan | 5 | 21 |
Feb | 8 | 20 |
Mar | 10 | 29 |
Apr | 18 | 32 |
May | 26 | 44 |
Jun | 35 | 58 |
Jul | 28 | 46 |
Aug | 20 | 32 |
Sep | 14 | 27 |
Oct | 8 | 13 |
Nov | 6 | 11 |
Dec | 26 | 52 |
| | |
a.Plot the data using Minitab. What kind of pattern do youobserve?
b.Develop a trend line equation for this data (Use Minitab).
c.Decompose the above time series using a multiplicative model.Store the trend line, detrended data, seasonals, seasonallyadjusted data. Then, calculate CI (Hint: CI = Deseasonalized data /Trend), C as a centered 3-moving average of CI values, and finallyI (=CI/C).
d.Next, compute forecasts for the next 6 months using the trendline equation and the seasonal indices you have computed. (Hint:What should you assume for C and I components?)
