An office building in New York uses thousands of fluorescent
light bulbs each year. The brand of bulb it currently uses has a
mean life of 900 hours. A manufacturer claims that it's new brand
of bulbs which cost the same as the brand the office building
currently uses has a mean life of more than 900 hours. The
university has decided to purchase the new brand if, when tested,
the test evidence supports the manufacturer's claim at the .05
significance level. Suppose 64 bulbs and the sample has a mean of
920 hours and a standard deviation of 80 hours. What are the null
hypothesis and the alternative hypothesis?