# Hypothesis Test Regarding a Population Mean Change

Not what you're looking for? Search our solutions OR ask your own Custom question.

Please show all steps.

The mean lifetime of electric light blubs produced by a company has in the past been 1120 hours with a standard deviation of 125 hours. A sample of 8 electric bulbs recently chosen from a supply of newly produced bulbs showed a mean lifetime of 1070 hours. Test the hypothesis that the mean lifetime of the bulbs has not changed, using a level of significance of (a) 0.05 and (b) 0.01

Â© BrainMass Inc. brainmass.com September 26, 2022, 6:57 pm ad1c9bdddfhttps://brainmass.com/statistics/hypothesis-testing/hypothesis-test-regarding-a-population-mean-change-29989

## SOLUTION This solution is **FREE** courtesy of BrainMass!

Please see the attached Word document for solution details.

Â© BrainMass Inc. brainmass.com September 26, 2022, 6:57 pm ad1c9bdddf>https://brainmass.com/statistics/hypothesis-testing/hypothesis-test-regarding-a-population-mean-change-29989