The business analyst for Video Sales, Inc. wants to forecast this year’s demand for DVD decoders based on the following historical data:
|5 years ago||900|
|4 years ago||700|
|3 years ago||600|
|2 years ago||500|
What is the forecast for this year using the naive approach?
What is the forecast for this year using a three-year weighted moving average with weights of .5, .3, and .2?
What is the forecast for this year using exponential smoothing with alpha = .4, if the forecast for two years ago was 750?
What is the forecast for this year using the least squares trend line for these data?
What is the forecast for this year using trend-adjusted (double) smoothing with alpha = .3 and beta = .2, if the forecast for last year was 310, the forecast for two years ago was 430, and the trend estimate for last year’s forecast was -150?
The chair of the operations management department at Quality University wants to construct a p-chart for determining whether the four faculty teaching the basic POM course are under control with regard to the number of students who fail the course. Accordingly, he sampled 100 final grades from last year for each instructor, with the following results:
|Instructor||Number of Failures|
What is the sample proportion of failures (p) for Prof. D? What is the estimate of the mean proportion of failures for these instructors?
What is the estimate of the standard deviation of the sampling distribution for an instructor’s sample proportion of failures?
What are the .95 (5 percent risk of Type I error) upper and lower control limits for the p-chart?
Using .95 control limits (5 percent risk of Type I error), which instructor(s), if any, should he conclude is (are) out of control?