If n =10, = 12 and ∑ x 2 = 1530 {\displaystyle \sum {x^{2}}=1530}
∑ x n = x ¯ {\displaystyle {\frac {\sum x}{n}}={\bar {x}}}
∑ x = x ¯ × n {\displaystyle \sum {x}={{\bar {x}}\times {n}}}
∑ x = 12 × 10 {\displaystyle \sum {x}={12\times {10}}}
∑ x = 120 {\displaystyle \sum {x}=120} σ= ∑ x 2 n − ( ∑ x n ) 2 {\displaystyle {\sqrt {{\frac {\sum {x^{2}}}{n}}-({{\frac {\sum x}{n}})^{2}}}}} σ= 1530 10 − 144 {\displaystyle {\sqrt {{\frac {1530}{10}}-{144}}}} σ= 153 − 144 {\displaystyle {\sqrt {153-144}}} σ= 9 {\displaystyle {\sqrt {9}}} σ=3
