Variance and standard deviation. Calculate the variance and the standard deviation of U$.$S$.$ Treasury$$ bills, long$-$term government$$ bonds, and$$ small$-$company stocks for $1950$ to$1959,1960$ to$1969,1970$ to$1979,$ and $1980$ to $1989$ from Table $8\mathrm{.}1.$ Which had the highest$$ variance? Which had the lowest$$ variance? Table long dash$$Year$-$by$-$Year $$Returns$,1950-1999.$