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

Job Category

Slept on the Job? IT Professional Government Professional
Yes 155 256
No 145 144


Choose the competing hypotheses to determine whether sleeping on the job is associated with job category.

a. H0: Sleeping on the job is independent of the job category.; HA: Sleeping on the job is dependent on the job category.
b. H0: Sleeping on the job is dependent on the job category.; HA: Sleeping on the job is independent of the job category.