A Federal Reserve Board Report looked at how consumers are using mobile devices throughout their purchase journey. In response to a survey question about mobile device use while shopping, 47% of smartphone owners said they use their smartphone to comparison shop on the Internet while at a retail store, 33% said they use a barcode scanning application for price comparisons, and 42% said they use their smartphone to get product reviews or product information while shopping at a retail store. Suppose the results are based on a survey of 300 smartphone owners. Construct a 95% confidence interval estimate of the population proportion of smartphone owners who said they use their mobile device while shopping to

a. Comparison shop on the Internet while at a retail shop.

b. Price compare with a barcode scanning application.

c. Get product reviews or product information while shopping at a retail store.

d. You have been asked to update the results of this study.

Determine the sample size necessary to estimate, with 95% confidence, the population proportions in (a) through (c) to within ± 0.02.