Measures of Dispersion

Standard deviation of a collection of data is $2\sqrt{2}$. If each value is multiplied by $3$, then the standard deviation of the new data is:

Draw the necessary table to find the Standard Deviation for the data $20, 14, 16, 30, 21$ and $25$.

For a collection of data if $\sum _{}^{}x=35,n=5,\sum _{}^{}{\left(x-9\right)}^2=82,$ then find $\sum _{}^{}{x}^2$ and $\sum _{}^{}{\left(x-\overline{x}\right)}^2$.

For a collection of data, if $\sum _{}x=35, n=5, \sum _{}{\left(x-9\right)}^2=82,$ then find $\sum _{}{x}^2$ and $\sum _{}{\left(x-\overline{x}\right)}^2$.

Variance of the first $11$ natural numbers is