Question 782:

Asked on July 14, 2009

Tags: 2-proportion test

A 20-minute consumer survey mailed to 500 adults aged 25–34 included a $5 Starbucks gift certificate.
The same survey was mailed to 500 adults aged 25–34 without the gift certificate. There
were 65 responses from the first group and 45 from the second group. (a) Perform a two-tailed test
comparing the response rates (proportions) at α = .05. (b) Form a confidence interval for the difference
of proportions, without pooling the samples. Does it include zero?

I really need to understand HOW to do this for our test next week. Please provide how you figured out the results.