Elementary Statistics (12th Edition)

Coefficient of variation=$\frac{standard \ deviation}{mean}$ By using the results from before: $cv_{W}=\frac{standard \ deviation}{mean}=\frac{2.9059}{73}=0.0398=3.98$% $cv_{AA}=\frac{standard \ deviation}{mean}=\frac{2.7487}{74}=0.0371=3.71$% White drivers' variation is bigger.