why-is-it-incorrect-to-use-sigma-x2-instead-of-sigma-x-squared-in-the-numerator-

Question

Why is it incorrect to use (Sigma $$x)^2$$ instead of Sigma x squared in the numerator of the standard deviation formula?

Accepted Answer

Because (Sigma $$x)^2$$ represents the square of the sum, not the sum of the squares, which leads to incorrect calculation of variance.

Answer

Because Sigma x squared is not used in any formula.

Answer

Because both values are always equal.

Answer

Because (Sigma $$x)^2 is $$always smaller.

Why is it incorrect to use (Sigma x)^2 instead of Sigma x squared in the numerator of the standard deviation formula?