An engineer wants to determine the effectiveness of a safety program. He collects annual loss of hours due to accidents in 12 plants “before and after” the program was put into operation. The data set, labeled Safety_Program, can also be found on the text website.

a. Specify the competing hypotheses that determine whether the safety program was effective.
b. Assuming that the hours differences are normally distributed, calculate the value of the test statistic.
c. At the 5% significance level, calculate the critical value(s).
d. Is there sufficient evident to conclude that the safety program was effective?Explain.

Transcribed Image Text:

Plant Before After Plant Before After 100 90 94 85 70 83 98 90 86 67 80 75 65 58 67 104 90 70 62 60 60 98 12