Suppose a consumer product researcher wanted to find out whether a Sharpie lasted longer than the manufacturer's claim that their Sharpies could write continuously for a mean of 14 hours. The researcher tested a random sample of 40 Sharpies and recorded the number of continuous hours each Sharpie wrote before drying up. The mean time (hours) from 40 sharpies is 14.5 hours and the standard deviation from 40 sharpies is 1.2 hours. Test the hypothesis that Sharpies can write for more than a mean of 14 continuous hours.

Which of the following is the most appropriate set of hypotheses?

Select one:

a.Ho: =14 vs. Ha: > 14

b.Ho: = 14 vs. Ha: 14

c.Ho: xbar =14 vs. Ha: xbar > 14

d.Ho: < 14 vs. Ha: > 14