Question

What is the variance of {15, 4, 2, -7, 8, 10}?

Answer 1

47.9

Explanation:

I'm going to assume you mean population variance (sample variance will differ slightly).

`sigma^2=(Sigmax^2-(Sigmax)^2/N)/N`

Please differentiate between the two. The first sign says "add the squares of your numbers", the second says "add first, THEN square the sum"

`Sigmax^2=15^2+4^2+...+10^2=458`
`(Sigmax)^2=(15+4+2+...)^2= 1024`
`N=6`

`sigma^2=(458-(1024/6))/6=47.9`