Risk based ranking from Highest to Lowest:
|Stocks||Standard Deviation(a)||Average Return(b)||Coefficient of Variation(a/b)|
2) We have given the risk ranking based on Coefficient of Variation, because it is ratio of standard deviation to mean.
3) If Coefficient of Variation is more, which means greater the dispersion around the mean and lower the Coefficient of Variation, the more precise the estimate. So, Stock with low Coefficient of Variation has more chance to meet estimation and less risk and high Coefficient of Variation stock has less chance to meet estimation and more risk..