The ratio of the variance of first n positive integral multiples of...

Let the variance of first $n$ natural numbers is ${\sigma}^{2}$ then the variance of first $n$ integral multiple of $4$ is $16{\sigma}^{2}$
and the variance of first $n$ odd natural numbers is $4{\sigma}^{2}$
Then, the required ratio is $\dfrac{16{\sigma}^{2}}{4{\sigma}^{2}} = 4$