\[\bar x=\frac{\sum_{i=1}^n x_i}{n},\qquad s^2=\frac{\sum_{i=1}^n(x_i-\bar x)^2}{n-1},\qquad s=\sqrt{s^2}.\]
\[IQR=Q_3-Q_1,\]
\[\text{lower fence}=Q_1-1.5IQR,\qquad \text{upper fence}=Q_3+1.5IQR.\]