Variance additivity for independent random variables
= Variance additivity for independent random variables
For independent square-integrable random variables,
$$
\operatorname{Var}\left(\sum_iX_i\right)
=\sum_i\operatorname{Var}(X_i).
$$
= Variance additivity for independent random variables
For independent square-integrable random variables,
$$
\operatorname{Var}\left(\sum_iX_i\right)
=\sum_i\operatorname{Var}(X_i).
$$