Thequality-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 7,458 hours. The population standard deviation is 100 hours. A random sample of 64 light bulbs indicates a sample mean life of 7,433 hours.

a. At the 0.05 level ofsignificance, is there evidence that the mean life is different from 7,458hours?

b. Compute thep-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 youreach?