An SRS of 101 postal employees found that the average time t

An SRS of 101 postal employees found that the average time these employees had worked for the postal service was x = 7 years, with standard deviation s = 2 years. Assume the distribution of the time the population of employees has worked for the postal service is approximately normal, with mean µ. Are these data evidence that µ has changed from the value of 7.5 years of 20 years ago? To determine this, we test the hypotheses H0: µ = 7.5, Ha: µ 7.5 using the one-sample t test. What is the appropriate degrees of freedom for this test? What is the range for the P-value for the one-sample t test? (show work) Is this significant at the 5% level? Is this significant at the 1% level? What is the 95% confidence interval for the population mean time µ that postal service employees have spent with the postal service? (show work)

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