The file P02_02.xlsx contains information on over 200 movies that came out during 2006 and 2007. Run a regression of Total US Gross versus 7-day Gross, and then run a multiple regression of Total US Gross versus 7-day Gross and 14-day Gross. Report the 95% confidence interval for the coefficient of 7-day Gross in each equation. What exactly do these confidence intervals tell you about the effect of 7-day Gross on Total US Gross? Why are they not at all the same? What is the relevant population that this data set is a sample from?