Sample variance

Description:

• Variance of a sample
• $S^2=\sum _{i=1}^n\frac{(X_i-\bar{X}{)}^2}{n-1}=\sum _{i=1}^n\frac{(X_i-\bar{X}{)}^2}{n-1}$ ????
• $E[S^2]={\sigma }^2$
  • Expected sample variance is the variance