# Devry BSOP 330 Week 1 Homework Exercises

November 28, 2016

Question
4.1 The following gives the number of pints of type A blood used at Woodlawn Hospital in the past 6 weeks:

Week Of
Aug-31
Sep-07
Sep-14
Sep-21
Sep-28
Oct-05

Pints used
360
389
410
381
368
374

a) Forecast the demand for the week of October 12 using a 3-week moving average.
(381+368+374) / 3 = 374

b) Use a 3-week weighted moving average, with weights of .1, .3, and .6, using .6 for the most recent week. Forecast demand for the week of October 12.
Weighted moving average = (weight for periods n)(demand in period n)
weights

c) Compute the forecast for the week of October 12 using exponential smoothing with a forecast for August 31 of 360 and = .2.

4.5 The Carbondale Hospital is considering the purchase of a new ambulance. The decision will rest partly on the anticipated mileage to be driven next year. The miles driven during the past 5 years are as follows: (Render 140)
year
1
2
3
4
5

Mileage
3000
4000
3400
3800
3700

a) Forecast the mileage for next year using a 2-year moving average.

b) Find the MAD based on the 2-year moving average forecast in part (a).(Hint: You will have only 3 years of matched data.)

c) Use a weighted 2-year moving average with weights of .4 and .6 to forecast next years mileage. (The weight of .6 is for the most recent year.) What MAD results from using this approach to forecasting? (Hint: You will have only 3 years of matched data.)

d) Compute the forecast for year 6 using exponential smoothing, an initial forecast for year 1 of 3,000 miles, and = .5. (Render 140)

4.9 Dell uses the CR5 chip in some of its laptop computers. The prices for the chip during the past 12 months were as follows:

a) Use a 3-month moving average and add the 3-month plot to the graph created in part (a).

c) Which is better (using the mean absolute deviation): the 2-month average or the 3-month average?

d) Compute the forecasts for each month using exponential smoothing, with an initial forecast for January of \$1.80. Use ? = .1, then ? = .3, and finally ? = .5. Using MAD, which ? is the best? (Render 141)

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