Use Finance Yahoo. During the past 5 years, across your selected group of rival corporations, which are which are Walmart, Amazon, Ebay, Alibaba and Target, which firms have earned a better risk-to-return trade-off (in terms of "smaller positive coefficient of variation" and/or "larger positive Jensen's Alpha") than peers? which firms have had relatively greater market risk levels (in terms of "Beta" value amount) than peers? Elaborate and focus on orginal data and thoughts on Walmart which is your target firm