Question 508946: Hypothesis test for the population mean: t test
An electronics manufacturing process has a scheduled mean completion time of 70 minutes. It is claimed that, under new management, the mean completion time, , is less than 70 minutes. To test this claim, a random sample of 17 completion times under new management was taken.
The sample had a mean completion time of 66 minutes and a standard deviation of 9.5 minutes. Assume that the population of completion times under new management is normally distributed. At the .05 level of significance, can it be concluded that the mean completion time, , under new management is less than the scheduled mean? That is, do you reject or not reject the null hypothesis? What is the critical value of t? Explain your decision fully with reference to the output.
Perform a one-tailed test.
Hypothesis Test: Mean vs. Hypothesized Value
70.00 hypothesized value
66.00 mean Etext1
9.50 std. dev.
2.30 std. error
17 n
16 df
-1.74 t
.0509 p-value (one-tailed, lower)
61.12 confidence interval 95.% lower
70.88 confidence interval 95.% upper
4.88 half-width
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Ho: u >= 70
Ha: u < 70 (claim)
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Since the p-value is greater than 5% you should fail to
reject Ho.
The test results do not support the claim.
However, the test results are so close to 5% that
testing should be continued.
Cheers,
Stan H.
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