Computing Return on Equity and Return on Assets

The following table contains financial statment information for Walmart Stores Inc.

$ millions	Total Assets	Net Income	Sales	Equity
2015	199,581	14,694	478,614	80,546
2014	203,490	16,363	482,229	81,394
2013	204,751	16,022	473,076	76,255

Questions

A. Compute the return on euqity (ROE) for 2014 and 2015. What trend, if any, is evident? How does Wal-Mart's ROE compare with approximately 18.9% ROE for companies in the Dow Jones INdustrial average of 2015?

B. Compute the return on assets for 2014 and 2015. What trends, if any, are evident? How does Wal-Mart's ROA compare with the approximate 7.1% median ROA for companies in the DOW Jones Industrial average for 2015?

C. What factors might allow a company like Walmart to reap above-average returns?