A market research consultant hired by a leading soft drink company wants to determine the proportion of consumers who favor its low-calorie brand over the leading low-calorie competitor in a particular geographic region. A random sample of 250 consumers from the market under investigation is provided in the file P08_17.xlsx. (Cannot put the file in here, the numbers are provided below. Sorry for the inconvenience).
a. Calculate a separate 90% confidence for each age group for the proportion who prefer the company's brand.
Count:
Less than 20 (Our brand: 15, Total: 21)
Between 20 and 40 (Total: 107, Our Brand: 57)
Between 40 and 20 (Total: 74, Our Brand: 40)
Over 60 (Total: 48, Our Brand: 22)