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# Hypothesis Testing: Two sample z test & Effect of Skewness

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Each response must include your calculations.
This problem requires you to complete all steps for the hypothesis testing process.
A cell phone company offers two plans to it subscribers. At the time new subscribers sign up, they are asked to provide some demographic information. The mean yearly income for a sample of 40 subscribers to Plan A is \$57,000 with a standard deviation of \$9,200. This distribution is positively skewed; the actual coefficient of skewness is 2.11. For a sample of 30 subscribers to Plan B the mean income is \$61,000 with a standard deviation of \$7,100. The distribution of Plan B subscribers is also positively skewed, but not as severely. The coefficient of skewness is 1.54.

Complete the following:

a. At the .05 significance level, is it reasonable to conclude the mean income of those selecting Plan B is larger?

b. What is the p-value? Report the p-value to 4 decimal places.

c. Do the coefficients of skewness affect the results of the hypothesis test? Why?