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Confidence Intervals and Hypothesis Test

The mean and standard deviation of the sample of 65 customer satisfaction ratings are x-bar = 42.95 and s = 2.6424. If we let "mu" denote the mean of all possible customer satisfaction ratings:

a) Calculate 95 and 99 percent confidence intervals for "mu".
b) Using the 95 percent confidence interval, can we be 95% confident that "mu" is greater than 42? Explain>

Suppose we wish to test H0: p = .8 versus Ha: p > .8 and that a random sample of n = 400 gives a
sample proportion = .86.
a Test H0 versus Ha at the .05 level of significance by using a rejection point. What do you conclude?

b Find the p-value for this test.

c Use the p-value to test H0 versus Ha by setting alpha equal to .10, .05, .01, and .001. What do you
conclude at each value of alpha?


Solution Summary

In this solution, formulas, calculation details and explanations are provided for two problems. The first problem finds 95 and 99 percent confidence intervals for a mean. The second problem conducts a hypothesis test for a mean.