Question

The director of the IRS has been flooded with complaints that people must wait more than 45 minutes before seeing an IRS representative. To determine the validity of these complaints, the IRS randomly selects 400 people entering IRS offices across the country and records the times that they must wait before  seeing an IRS representative. The average waiting time for the sample is 55 minutes with a standard deviation of 15 minutes.

Are the complaints substantiated by the data at alpha level of 0.10?

**** Please include all these Steps in order****

Step 1 : Define the hypothesis to be tested for Null hypothesis and Alternative hypothesis.

Step 2: Select the appropriate statistical measure, such as the population mean, proportion, or variance

Step 3: Determine whether the alternative hypothesis should be one-sided or two-sided.

Step 4: State the hypotheses using the statistical measure found in Step 2

Step 5: Specify α, the level of the test. α =_______

Step 6: Select the appropriate test statistic based on the information at hand and the assumptions you willing to make. Normal distribution

Step 7 : Determine the critical value of the test statistic

Step 8: Collect sample data and compute the value of the test statistic.

Step 9: Make the decision

Step 10 : State the conclusion in terms of the original question

Answer 1

Step 3 - The alternative hypothesis is one sided.

Step 5 -

Step 6 - since sample is very large ( > 30), using central limit theorem, we can assume sampling distribution of sample mean as normal distribution.