Question: A manufacturer of light bulbs likes its bulbs to have a mean bulb life of at least 2100 hours. A sample of twenty bulbs tested produced the following results for bulb life, in hours:

a) Using a confidence interval, is there enough evidence to indicate the mean life of the light bulbs from this manufacturer is above 2100 hours? Use a significance level of 0.02.

b) Using a hypothesis test, is there enough evidence to indicate the mean life of the light bulbs from this manufacturer is above 2100 hours? Use a significance level of .01. (NOTE: Assume that the bulb life for these particular bulbs is normally distributed.)