A market research consultant hired by a leading soft drink company wants to determine the proportion of consumers who favor its low-calorie drink over the leading competitor’s low-calorie drink in a particular urban location. A random sample of 250 consumers from the market under investigation is provided in the file P08_18.xlsx.
a. Find a 95% confidence interval for the proportion of all consumers in this market who prefer this company’s drink over the competitor’s. What does this confidence interval tell us?
b. Does the confidence interval in part a support the claim made by one of the company’s marketing managers that more than half of the consumers in this urban location favor its drink over the competitor’s? Explain your answer.
c. Comment on the sample size used in this study. Specifically, is the sample unnecessarily large? Is it too small? Explain your reasoning.