If each of the observation `x_1,x_2,dotdotdot,x_n`is increased by a where a is a negative or positive number, show that the variance remains unchanged.

Explanation

Let the mean of the observation `x_1,x_2,........x_n` be `barx`


variance of these observations is given by


old variance `=(1/n) sum(x_i-barx)^2`.........(1)


if each observation is increased by `a` we get new observations,


...