Case Study on Cell Phones

Research Question: "Are you annoyed when cell phones go off in quiet public places?"

A SRS of n1 = 220 people between the ages of 18 and 30 were asked, and 108 said YES

A SRS of n2 = 316 people between the ages of 31 and 50 were asked, and 186 said YES

Let p1 be the proportion of 18-30 yr olds in the population that are annoyed by cells ringing.

Let p2 be the proportion of 31-50 yr olds in the population that are annoyed by cells ringing.

1. Find a 95% confidence interval for p1-p2

2. Conduct a hypothesis test that Ho: p1-p2 = 0 versus Ha: p1-p2 not equal to 0