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Z test for one sample mean

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A furniture store claims that a specially ordered product will take, on average,28 = days (4 weeks) to arrive. The standard deviation of these waiting times is 7 days. We suspect that the special orders are taking longer than this. To test this suspicion, we track a random sample of 80 special orders and find that the orders took a mean of 30 days to arrive. Can we conclude at the 0.05 level of significance that the mean waiting time on special orders at this furniture store exceeds 28 days?

Perform a one-tailed test.

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Solution Summary

Step by step method for computing test statistic for Z test is given in the answer.

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