A light bulb manufacturer guarantees that the mean life of a

A light bulb manufacturer guarantees that the mean life of a certain type of light bulb is at least 762 hours. A random sample of 21 light bulbs has a mean life of 751 hours. Assume the population is normally distributed and the population standard deviation is 57 hours. At =0.08, do you have enough evidence to reject themanufacturer\'s claim? Complete parts (a) through (e).

(a) Identify the null hypothesis and alternative hypothesis.

A.H0:<751(claim)

Ha:751

B.H0:=751

Ha:751(claim)

C. H0:762 (claim)

Ha: <762

D. H0: >762

Ha:762 (claim)

E. H0: 751

Ha:>751 (claim)

F.H0:u762(claim)

Ha:=762

(b) Identify the critical value(s). Use technology.

z0=______?
(Use a comma to separate answers as needed. Round to two decimal places as needed.)

c) Identify the standardized test statistic. Use technology.

zequals=______?
(Round to two decimal places as needed.)

(d) Decide whether to reject or fail to reject the null hypothesis, and (e) interpret the decision in the context of the original claim.

A.Fail to reject H0.There is sufficient evidence to reject the claim that mean bulb life is at least 762 hours.

B. Reject H0.There is sufficient evidence to reject the claim that mean bulb life is at least 762 hours.

C.Fail to reject H0.There is not sufficient evidence to reject the claim that mean bulb life is at least 762 hours.

D.Reject H0.There is not sufficient evidence to reject the claim that mean bulb life is at least 762 hours.

Solution