Complete the following:
Hypothesis test for the population mean: Z test
A manufacturer claims that the mean lifetime, μ of its light bulbs is months. The standard deviation of these lifetimes is 44 months. Ninety bulbs are selected at random, and their mean lifetime is found to be 8 months. Can we conclude 0.05 at the level of significance, that the mean lifetime of light bulbs made by this manufacturer differs from 43 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: Ho =
The alternative hypothesis: H1 =
The type of test statistic =
The value of the test statistic (round to at least 3 decimal places) =
The two critical values at the 0.05 level of significance (round to at least 3 decimal places) =
Can we conclude that the mean lifetime of the light bulbs made by this manufacturer differs from 44 months?