Question 1153190: A manufacturer claims that the mean lifetime,
μ
, of its light bulbs is
45
months. The standard deviation of these lifetimes is
4
months. Ninety bulbs are selected at random, and their mean lifetime is found to be
44
months. Can we conclude, at the
0.05
level of significance, that the mean lifetime of light bulbs made by this manufacturer differs from
45
months?
Perform a two-tailed test. Then fill in the table below.
Carry your intermediate computations to at least three decimal places, and round your responses as specified in the table.
The null hypothesis:
H
0
:
The alternative hypothesis:
H
1
:
The type of test statistic:
The value of the test statistic:
(Round to at least three decimal places.)
The two critical values at the
0.05
level of significance:
(Round to at least three decimal places.)
and
Can we conclude that the mean lifetime of light bulbs made by this manufacturer differs from 45 months?
Answer by ikleyn(52884)   (Show Source):
You can put this solution on YOUR website! .
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Otherwise, you will regularly find your posts in the TRASH SECTION, zeroed.
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