1.
If ∑i=1n(xi−a)=n\sum_{i=1}^{n}(x_i - a) = n and ∑i=1n(xi−a)2=na\sum_{i=1}^{n}(x_i - a)^2 = na, with n,a>1n, a > 1, then the standard deviation of the nn observations x1,x2,…,xnx_1, x_2, \ldots, x_n is: