Question

The quality-control manger at a compact fluorescent light bulb (CFL) factory needs to determine whether the mean life of a large shipment of CFLs is equal to 7,500 hours. The population standard deviation is 1,000 hours. A random sample of 64 CFLs indicates a sample mean life of 7,250.

a) At the 0.05 level of significance, is there evidence that the mean life is different from 7,500 hours?

b) Complete the p-value and interpret its meaning.

c) Construct a 95% confidence interval estimate of the population mean life of the CFLs.

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

Answer 1