Answer
$R=45~thousand~dollars
$
The population variance:
$σ^2=160~(thousand~dollars)^2$
The population standard deviation:
$σ=12.65~thousand~dollars$
Work Step by Step
$R=largest~value-smallest~value=75-30=45$
The mean:
$μ=\frac{30+30+45+50+50+50+55+55+60+75}{10}=50$
The population variance:
$σ^2=\frac{Σ(x_i-μ)^2}{n}=\frac{(30-50)^2+(30-50)^2+(45-50)^2+(50-50)^2+(50-50)^2+(50-50)^2+(55-50)^2+(55-50)^2+(60-50)^2+(75-50)^2}{10}=160$
The population standard deviation:
$σ=\sqrt {160}=12.65$
