Question

The​ quality-control manager at a compact fluorescent light bulb​ (CFL) factory needs to determine whether the mean life of a large shipment of CFLs is equal to

7,538 hours. The population standard deviation is 92 hours. A random sample of 6464 light bulbs indicates a sample mean life of 7,515 hours.

a. At the 0.05 level of​ significance, is there evidence that the mean life is different from 7,538 hours?

b. Compute the​ p-value and interpret its meaning.

c. Construct a 95​% confidence interval estimate of the population mean life of the light bulbs.

d. Compare the results of​ (a) and​ (c). What conclusions do you​ reach?

Answer 1