Question

What is the variance of the following numbers?: {4,7,4,2,1,4,5}

Answer 1

3.27

Explanation:

Variance = `sumx^2/n` -`(mean)^2`

Mean = `sum(x) / n` where n in the number of terms
= `(4+7+4+2+1+4+5)/7`
= `(27)/7`
= 3.857

`sumx^2` = `4^2 + 7^2 + 4^2 + 2^2 + 1^2 + 4^2 + 5^2`
= 127

SO Variance = `127/7` - `(3.857)^2`
= 3.27