Repeat Problem 65, but now stratify the consumers in the given frame by age rather than by gender. How does this modification affect your answers to the questions posed in parts b and c? Finally, stratify the consumers by both gender and age (e.g., all females over 60) with proportional sample sizes. How does this change affect your answers to the questions posed in parts b and c? Which approach to stratification appears to give the best results in estimating the actual proportion of the customers in the given frame who favor Pepsi?

Data from in problem 65

A market research consultant hired by the Pepsi-Cola Co. is interested in determining who favors the Pepsi-Cola brand over Coke Classic in a particular urban location. A frame of customers from the market under investigation is provided in P8_44.XLS.