Response rates to Web surveys are typically low, partially due to users starting but not finishing the survey. The factors that influence response rates were investigated in Survey Methodology (December 2013). In a designed study, Web users were directed to participate in one of several surveys with different formats. For example, one format utilized a welcome screen with a white background and another format utilized a welcome screen with a red background. The "break-off rates," i.e., the proportion of sampled users who break off the survey before completing all questions, for the two formats are provided in the table.

a. Verify the values of the break-off rates shown in the table.
b. The researchers theorize that the true break-off rate for Web users of the red welcome screen will be lower than the corresponding break-off rate for the white welcome screen. Give the null and alternative hypotheses for testing this theory.
c. Compute the test statistic for the test.
d. Find the p-value of the test.
e. Make the appropriate conclusion using α = .10.

White Welcome Red Welcome Screen 190 49 Screen Number of Web users Number who break off survey Break-off rate 183 37 .258 .202