Question

What is the variance of {-2, 5, 18, -8, -10, 14, -12, 4}?

Answer 1

Variance `sigma^2=6903/64=107.8593`

Explanation:

compute the arithmetic mean `mu` first

`n=8`

`mu=(-2+5+18+(-8)+(-10)+14+(-12)+4)/8`

`mu=(-32+41)/8`

`mu=9/8`

compute the variance `sigma^2` using the variance formula for population

`sigma^2=(sum(x-mu)^2)/n`

`sigma^2=((-2-9/8)^2+(5-9/8)^2+(18-9/8)^2+(-8-9/8)^2+(-10-9/8)^2+(14-9/8)^2+(-12-9/8)^2+(4-9/8)^2)/8`

`sigma^2=6903/64`

`sigma^2=107.8593`

God bless ....I hope the explanation is useful.