As a marketing associate for a sports apparel company, we see that, in 2011, 44.2% of our customers checked reviews of our new products on social media sites before buying. This year, to see if that percentage has increased, we use an email campaign to survey our recent customers. Of 39,994 respondents, 17,885 said that, before buying, they checked reviews of the product they purchased on social media.

a.)Based on this survey, what is the point estimate of the proportion of our customers who check social media reviews?

b.)Test whether the increase indicated by this point estimate is statistically significant?

c.)Compute a 95% confidence interval for the percentage of customers using social media before buying. What do we think about it?

d.)What is the power of the test in part b?

e.)Based on this analysis, would you recommend any changes in our social media marketing approach?