Must show work in excel.
7.1. If purchases were 45% of sales and other expenses were 45% of sales, what would be the increase in
profit if, through better purchasing, the cost of purchases was reduced to 43% of sales?
7.2. If suppliers were to be rated on the following basis, what would be the ranking of the two suppliers
listed?
7.3. A company is negotiating with a potential supplier for the purchase of 100,000 widgets. The
company estimates that the supplier’s variable costs are $5 per unit and that the fixed costs,
depreciation, overhead, and so on, are $50,000. The supplier quotes a price of $10 per unit. Calculate
the estimated average cost per unit. Do you think $10 is too much to pay? Could the purchasing
department negotiate a better price? How?
8.2. Given the following data, calculate the three-month moving average forecasts for months 4, 5, 6,
and 7.
8.5. If the old forecast is 100 and the latest actual demand is 83, what is the exponentially smoothed
forecast for the next period? Alpha is 0.25.
8.8. Weekly demand for an item averaged 100 units over the past year. Actual demand for the next eight
weeks is shown in what follows:
A. Plot the data on graph paper.
B. Letting A = 0.25, calculate the smoothed forecast for each week.
C. Comment on how well the forecast is tracking actual demand. Is it lagging or leading actual
demand?
8.12. Given the following average demand for each month, calculate the seasonal indices for each
month.
Note that your answer, if done correctly, should have all the seasonal indices add up to the number of
periods in the entire season, in this case 12.
8.13. Using the data in problem 8.12 and the seasonal indices you have calculated, calculate expected
monthly demand if the annual forecast is 2000 units.
8.19. For the following data, calculate the mean absolute deviation.
8.20. A company uses a tracking signal trigger of ±4 to decide whether a forecast should be reviewed.
Given the following history, determine in which period the forecast should be reviewed. MAD for the
item is 15. Is there any previous indication that the forecast should be reviewed?