Rank the following three stocks by their level of total risk, highest

to lowest. Rail Haul has an average return of $12$ percent and

standard deviation of $25$ percent. The average return and standard

deviation of Idol Staff are $15\%$ and $35\%$; and of Poker$-$R$-$Us are $9$

percent and $20$ percent. Before solving this problem, calculate the

coefficient of variation.