Question

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 day shift. The mean number of units produced by a sample of 59 day-shift workers was 323. The mean number of units produced by a sample of 67 night-shift workers was 333. Assume the population standard deviation for the number of units produced on the day shift is 19 and is 27 on the night shift. At the 0.10 significance level, is the number of units produced on the night shift larger? a) Is this a one-tailed or two-tailed test? b) State the decision rule. c) Compute the value of the test statistic. d) What is your decision regarding Ho?

Answer 1

from above

a)

this is one tailed test

b)

Decision rule : reject Ho if test statistic z>1.28 (try z<-1.28 if this comes wrong)

c)

value of the test statistic z =2.43 (try -2.43 if this comes wrong)

d)

reject the null since test statistic > critical value