Question: Exercise presented a table in which men were classified according to whether or not they had a pierced ear and a tattoo. Of the 424 men with no pierced ear, 43 had a tattoo. Of the 141 men with at least one pierced ear, 42 had a tattoo. Assuming that these men are a random sample of college men, test the hypothesis that college men with at least one ear pierced are more likely to have a tattoo than college men with no ears pierced. Show all five steps of the hypothesis testing procedure. Be sure to specify the value of a that you chose to use.

Exercise: In the table below are data collected between 1996 and 1998 on ear piercing and tattoos for male Penn State students. Assume that these men represent a random sample of male Penn State students. The results were as follows:

a. For the population of men with no ears pierced, find a 90% confidence interval for the proportion with a tattoo.

b. For the population of men with an ear pierced, find a 90% confidence interval for the proportion with a tattoo.

c. Find a 99% confidence interval for the difference in proportions of men with a tattoo for the populations with and without an ear piercing. Write a sentence interpreting the interval.