Please help me with solving questions (a), (b) and (c). Provide all the steps to get to the final solution. Thanks a lot!

A researcher is interested in examining the impact of illegal music downloads on commercial music sales. He collects data on commercial sales of the top 500 singles (y) and the number of downloads from a website that allows illegal file sharing (:12), and estimates a regression model of the form y;- = .60 + 613;- + in and gets a large positive estimated parameter 61. The author concludes these results demonstrate that downloads actually spur on music sales. (a) Write the expression for the s.e. of .31. What happens to the standard error if the sample size increases from n. to 211? (b) Is the estimator .31 a good estimate of the impact of illegal music sales? Why or whj.r not? (c) If not, do ~you expect '31 to overstate or understate the relationship between 3; and :12? In other words, is 31 upward or downward biased, and why