Answer to Question #133331 in Statistics and Probability for Stevphy

Question

How to find variance of a sample

Answer 1

Let's assume that we have a sample $X_1, X_2, ..., X_n$.

The variance of a sample is

$\sigma^2 = Var[X] = \displaystyle \frac{1}{n-1} \sum_{i=1}^n (X_i - \mu)^2$

where $\mu =\displaystyle \frac{1}{n} \sum_{i=1}^n X_i$