Question

What is the variance of {15, 14, 13, 13, 12, 10, 7}?

Answer 1

Variance of the data set is `6.29`.

Explanation:

Note that the formula of variance for calculation purpose is

`1/n sum_(i=1) ^n x_i^2 - (1/n sum_(i=1)^n x_i)^2`

where `n` is the total number of values in the given data set.
In your given data we have `n = 7` and the values of `x_i`'s are `{15, 14, 13, 13, 12, 10, 7}` .

So, your variance `= 1/7 [ 15^2+14^2+ 13^2 +13^2+12^2+10^2+7^2 ] - (1/7 *[ 15+14+13+13+12 +10 +7])^2`
`= 150. 29 -144`
`=6.29`