Seven years worth of returns for stock W and for the S&P 500, Rm, are listed below. Compute the estimated beta of stock W.

Year    Stock W      S&P 500, Rm

2011      7.8%             4.2%

2012     12.1%            7.9%

2013     11.5%             6.8%

2014     23.6%             7.3%

2015       8.2%            1.4%

2016    -12.4%            1.1%

2017      27.9%         14.7%