Question

A light bulb manufacturer guarantees that the mean life of a certain type of light bulb is at least 757 hours. A random sample of 22 light bulbs has a mean life of 729 hours. Assume the population is normally distributed and the population standard deviation is 65 hours. At a=0.02​, do you have enough evidence to reject the​ manufacturer's claim.

1. identify null and alternative hypothesis

2.identify region rejections on graph

3.identify standarized test statstics

4. interpret decision

Answer 1

Solution-

1) Null and alternative hypothesis

2) rejection region-

3) Test statistic -

4) decision and interpretation-

by the test results null hypothesis Ho is not rejected.

So, there is not enough evidence to support the manufacturer claim that the mean life of certain type of light bulb is at least 757 hours.