State University Uses Thousands of Fluorescent Light Bulbs Each Year $\bar { x }$

Essay

State University uses thousands of fluorescent light bulbs each year. The brand of bulb it currently uses has a mean life of 800 hours. A competitor claims that its bulbs, which cost the same as the brand the university currently uses, have a mean life of more than 800 hours. The university has decided to purchase the new brand if, when tested, the evidence supports the manufacturer's claim at the .05 significance level. Suppose 121 bulbs were tested with the following results: $\bar { x }$ = 827.5 hours, s = 110 hours. Conduct the test using α = .05.