The beta coefficient for Stock $C$ is $b_C=0\mathrm{.}4$ and that for Stock $D$ is $b_D=-0\mathrm{.}5.($Stock

D$\text{'}$s beta is negative, indicating that its rate of return rises whenever returns on most

other stocks fall. There are very few negative$-$beta stocks, although collection agency

and gold mining stocks are sometimes cited as examples.$)$