7. A researcher is interested in examining the impact of illegal music downloads on commercial music sales. The author collects data on commercial sales of the top 500 singles from 2007 (Y) and the number of downloads from a web site that allows 'file sharing' (X(). The author estimates an OLS model of the form Y,=0, +X; B, +s; and the author gets a large positive coefficient on the estimated parameter / . The author concludes these results demonstrate that downloads actually spur on music sales. Is this an unbiased estimate of the impact of illegal music on sales? Why or why not? Do you expect the estimate to overstate or understate the true relationship between Y and X, and does the original conclusion of a positive relationship hold