Use Excel to solve the following problems. Failure to use excel will result in a score of zero for the question.

1. The monthly sales of a new business software package at a local discount software store were as follows:

Week    1        2        3         4        5        6       7       8        9        10

Sales   460    415    432     450    488     512   475    502     449    486

1. Plot the data and provide insights about the time series.
2. Find the best number of weeks to use in a moving-average forecast based on MSE.
3. Find the best single exponential smoothing model to forecast these data.
1. Consider the quarterly sales data for Worthington Health Club shown here (also available on the worksheet C9P9 in the Data Workbook):

Quarter                      Total

Year      1          2         3           4         Sales

1           4         2         1           5           12

2           6         4         4         14           28

3          10         3         5         16           34

4          12         9         7         22           50

5          18         10      13         35           76

1. Develop a four-period moving average model and compute MSE for your forecasts.
2. Find a good value of a for a single exponential smoothing model and compare your results to part (a).
3. Using the factory energy cost data in the spreadsheet, find the best moving average and exponential smoothing models. Compare their forecasting ability with the regression model developed in the chapter.  Which model would you choose and why?
4. The president of a small manufacturing firm is concerned about the continual growth in manufacturing costs in the past several years. The data series of the cost per unit for the firmâ€™s leading product over the past eight years are given as follows:

Year  Cost/Unit (\$)     Year    Cost/Unit (\$)

1              20.00              5             26.60

2              24.50              6             30.00

3              28.20              7             31.00

4              27.50              8             36.00

1. Construct a chart for this time series. Does a linear trend appear to exist?
2. Develop a simple linear regression model for these data. What average cost increase has the firm been realizing per year?