15. According to an online survey by Harris Interactive for jo b site CareerBuilder.com (lnformationWeek.com, September 27, 2007), more than half o f IT workers say they have fallen asleep at work. Sixty-four percent o f government workers admitted to falling asleep on the job. Assume that the following contingency table is representative o f the survey results.

Slept on the Job?

Job Category IT Professional Government Professional Yes 155 256 No 145 144

a. Specify the competing hypotheses to determine whether sleeping on the jo b is associated w ith jo b category.

b. Compute the value o f the test statistic.

c. Approximate the p -value.

d. At the 5% significance level, can you conclude that sleeping on the jo b depends on jo b category?