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Sample Size Required - Food Poisoning

Please help with the following problem.

Recently, a case of food poisoning was traced to a particular restaurant chain. The source was identified and corrective actions were taken to make sure that the food poisoning would not reoccur. Despite the response from the restaurant chain, many consumers refused to visit the restaurant for some time after the event. A survey was conducted three months after the food poisoning occurred with a sample of 319 patrons contacted. Of the 300 contacted, 30 indicated that they would not go back to the restaurant because of the potential for food poisoning. What sample size would be needed in order to be 99% confident that the sample proportion is within .02 of p, the true proportion of customers who refuse to go back to the restaurant? Use the appropriate sample size formula to find the solution and show work.

A. 865
B. 4148
C. 609
D. 1,494
E. 1,218

Solution Summary

This solution provides brief and easy to understand calculations for determining the sample size required for the study.