Given:
The data is,
[tex]11,8,6,9,12,10,12,12,13,12,8,9,9,9,13,11,11,6,12,11[/tex]
The mean of given data is,
[tex]\bar{x}=10.2[/tex]
The varience is given as,
[tex]\begin{gathered} s^2=\sum ^n_{i=1}\frac{\left(x_i-\bar{x}\right)^2}{n-1} \\ =\frac{1}{20-1}\lbrack(11-10.2)^2+(8-10.2)^2+(6-10.2)^2+(9-10.2)^2+(12-10.2)^2+(10-10.2)^2+(12-10.2)^2+(12-10.2)^2+(13-10.2)^2+(12-10.2)+(8-10.2)^2+(9-10.2)^2+(9-10.2)^2+(9-10.2)^2+(13-10.2)^2(11-10.2)^2+(11-10.2)^2+(6-10.2)+(12-10.2)^{22}+(11-10.2)^2\rbrack \\ =\frac{85.2}{19} \\ =4.48 \end{gathered}[/tex]
So, the value of varience is ,
[tex]s^2=4.48[/tex]
The standard deviation is,
[tex]s=\sqrt[]{4.48}=2.12[/tex]
