For n n\,n observations x1,x2,…,xnx_1,x_2,\ldots,x_nx1,x2,…,xn, the variance is ∑x2n−xˉ2\dfrac{\sum x^2}{n}-\bar{x}^2n∑x2−xˉ2. A constant c c\,c is added to every observation.
Show algebraically that the variance is unchanged.