1. Clark Heter is an industrial engineer at Lyons Products. He would like to determine whether there are more units produced on the night shift than on the days shift. Assume the populations standard deviation for the number of units produced on the days shift is 21 and is 28 on the night shift. A sample of 54 day shift workers showed that the mean number of units produced was 345. A sample of 60 night shift workers showed that the mean numbers of units produced was 351. At the .05 significant level, is the number of units produced on the night shift larger? Explain.
2. A number of minor automobile accidents occur at various high -risk intersections in Teton County despite traffic lights. The Traffic Department claims that a modification in the type of light will reduce these accidents. The county commissioners have agreed to a proposed experiment. Eight intersections were chosen at random, and the lights at those intersections were modified. The numbers of minor accidents during a six-month period before and after the modifications were:
Number of Accidents
A B C D E F G H
Before modification 5 7 6 4 8 9 8 10
After modification 3 7 7 0 4 6 8 2
At the .01 significant level is it reasonable to conclude that the modification reduced the number of traffic accidents?
3. The following data on annual rates of return were collected from five stocks listed on the population standard deviations are the same. At the .10 significant level, can we conclude that the annual rates of return are higher on the big board?
The solution provides step by step method for the calculation of test statistics for hypothesis testing problem . Formula for the calculation and Interpretations of the results are also included. Interactive excel sheet is included. The user can edit the inputs and obtain the complete results for a new set of data.