Answer
The variance:
$σ^2=16$
The standard deviation:
$σ=4$
Work Step by Step
At first, let's evaluate the population mean:
$μ=\frac{3+6+10+12+14}{5}=9$
Now, the variance:
$σ^2=\frac{Σ(x_i-μ)^2}{n}=\frac{(3-9)^2+(6-9)^2+(10-9)^2+(12-9)^2+(14-9)^2}{5}=\frac{36+9+1+9+25}{5}=16$
The standard deviation:
$σ=\sqrt {16}=4$
