The quality-control manager at a compact fluorescent light bulb (CFL) factory needs to determine whether the mean life of a large shipment of CFLs is equal to

7,540

hours. The population standard deviation is

700hours.

A random sample of

49

light bulbs indicates a sample mean life of

7,390

hours.

a. At the

0.05

level of significance, is there evidence that the mean life is different from 7,540hours?

b. Compute the p-value and interpret its meaning.

c. Construct a

95%

confidence interval estimate of the population mean life of the light bulbs.

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

Question content area bottom

Part 1

a. Let

be the population mean. Determine the null hypothesis,

H0,

and the alternative hypothesis,

H1.

H0:

=75407540

H1:

75407540

Part 2

What is the test statistic?

ZSTAT=negative 1.501.50

(Round to two decimal places as needed.)

Part 3

What is/are the critical value(s)?

enter your response here

(Round to two decimal places as needed. Use a comma to separate answers as needed.)