Before changes to its management staff, an automobile assembly line operation had a scheduled mean completion time of 13.3 minutes. The standard deviation of completion times was 1.8 minutes. An analyst at the company suspects that, under new management, the mean completion time, μ, is now less than 13.3 minutes. To test this claim, a random sample of 80 completion times under new management was taken by the analyst. The sample had a mean of 12.8 minutes. Can we support, at the 0.01 level of significance, the claim that the population mean completion time under new management is less than 13.3 minutes? Assume that the population standard deviation of completion times has not changed under new management. Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places, and round your responses as specified below. A. Find the value of the test statistic and round to 3 or more decimal places. (I have posted a picture of an example problem and the equation to use, with the correct answer as every expert I have asked thus far has gotten this problem wrong.) B. Find the p-value C. Can we support the claim that the population mean completion time under new management is less than 13.3 minutes? (yes or no)
Before changes to its management staff, an automobile assembly line operation had a scheduled mean completion time of 13.3 minutes. The standard deviation of completion times was 1.8 minutes. An analyst at the company suspects that, under new management, the mean completion time, μ, is now less than 13.3 minutes. To test this claim, a random sample of 80 completion times under new management was taken by the analyst. The sample had a mean of 12.8 minutes. Can we support, at the 0.01 level of significance, the claim that the population mean completion time under new management is less than 13.3 minutes? Assume that the population standard deviation of completion times has not changed under new management. Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places, and round your responses as specified below.
A. Find the value of the test statistic and round to 3 or more decimal places. (I have posted a picture of an example problem and the equation to use, with the correct answer as every expert I have asked thus far has gotten this problem wrong.)
B. Find the p-value
C. Can we support the claim that the population mean completion time under new management is less than
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