1. Use data from Market Insight (www.mhhe.com/edumarketinsight) to calculate the beta of General Motors (GM). Start by obtaining the monthly rates of return of GM and the S&P 500 over the most recent 3 years. Enter these returns in an Excel spreadsheet. Plot the returns and then draw by eye the best line through the points. What is the slope of the line? How much does GM's return increase on average given a 1-percentage-point increase in the market return? Now use the regression (slope) function in Excel, calculate a regression with GM's return as the dependent variable and the S&P 500 return as the explanatory variable. What is GM's beta?