Question

1. (30)  For many decades, a company has monitored the stress experienced by its employees using a questionnaire that has an overall mean of 60 for the company---this mean is based on thousands of employee questionnaires. Three of the company's directors have just been arrested for fraud, and the company wants to know if the arrests have caused an increase in stress among the employees.  A sample of 30 employees is given the questionnaire; the mean for the sample is 71, and the standard deviation is 8.70.

a. (6) Set up the null and alternative hypotheses in formal terms.

b. (12) Test the null hypothesis.   Use α = .05. (Round final answer to 4 decimal places.)

c. (6) State your decision regarding the null hypothesis. Be sure to support your answer; that is, tell tell me with numbers the information that you used to make your decision.  

d. (2) Do the analyses indicate that there has been an increase in stress?

  YES NO

e. (4). Could you have made a statistical decision error in Part c? If so, name and define the decision error.

Answer 1