A stock or a investment portfolio can not be judged by just its past returns. It has to be rated with how risky it is in order to see if it's worth investing. The return per unit of risk means, how much return do I get as per how much risk I take. Also, we want to measure the return less of risk free rate, because if a risky can not generate return a return better than the risk free rate, why would I invest in it? What I am talking about is actually a famous investment term, the "Sharpe ratio", which has a formula of this: (Return - Risk Free Rate) / Portfolio Standard Deviation Sharpe Ratio Calculator By Mean and Standard deviation Risk Free Rate: % Mean Return: % Return Standard Deviation: % Submit The Sharpe Ratio is Sharpe Ratio Calculator By Entering A Series of Stock Prices, Seperated by Commas Risk Free Rate: % 10,20,30 Returns: Mean Return: % Return Standard Deviation: % S...