In a Nielsen global online survey of about 27,000 people from 53 different countries, 61% of consumers indicated that they purchased more store brands during the economic downturn and 91% indicated that they will continue to purchase the same number of store brands when the economy improves. The results were remarkably consistent across all regions of the world. The survey was conducted during September 2010 and had quotas for age and gender for each country, and the results are weighted to be representative of consumers with Internet access.
(a) What is the sample? What is an appropriate population?
(b) Find and interpret a 99% confidence interval for the proportion of consumers who purchased more store brands during the economic downturn.
(c) Find and interpret a 99% confidence interval for the proportion of consumers who will continue to purchase the same number of store brands.