Question

Find the mean, variance, and standard deviation for the data set.13 7 13 8 9

Answer 1

Proceed as follow:

the mean is given by:

`\bar{x}=(13+7+13+8+9)/(5)=10`

that is, the sum of all data over the number of data.

the standard deviation is:

`\begin{gathered} s=\sqrt[]{\frac{\Sigma(x-\bar{x})^2}{n-1}} \\ s=\sqrt[]{((13-10)^2+(7-10)^2+(13-10)^2+(8-10)^2+(9-10)^2)/(5-1)} \\ s=\sqrt[]{(32)/(4)}=\sqrt[]{8}\approx2.8 \end{gathered}`

the variance is:

`s^2=8`