Instagram has become an essential tool for social marketing. It boasts 400 million monthly active users, 80 million posts each day, and 3.5 billion daily likes. An audience that engaged is hard to ignore, and as of today, 90% of the top brands in the world are using Instagram to get their piece of the proverbial pie. The main goal is user engagement. Use the Excel file Instagram.xlsx to estimate what determines engagement. The file includes data on User Engagement, Followers, Videos, and Photos.

a. Test the significance of each independent variable using α = 0.05.

b. Construct a 95% confidence interval for each regression coefficient and interpret the meaning.