Question

A research firm wants to be 90 percent confident that a population percentage of people who prefer chocolate ice cream over vanilla that has been estimated to be within 3 percentage points. Suppose that a study designed to collect new data on search engine preferences uses a preliminary estimate of the proportion of people who prefer chocolate over vanilla as 56 percent. A) How large a sample must be taken to estimate the proportion of people who prefer chocolate over vanilla? B) Assume now that your study uses this sample size and find that 400 people in the sample prefer chocolate over vanilla. What is the point estimate for the proportion of people who prefer chocolate over vanilla? C) Finally, using your point estimate, calculate the 90 percent confidence interval for the proportion of people who prefer chocolate over vanilla

Answer 1