Question

What is the variance of {1000, 600, 800, 1000}?

Answer 1

Variance is `27500`

Explanation:

The mean of data set is given by the sum of data divided by their number i.e. `(Sigmax)/N`

Hence mean is `1/4(1000+600+800+1000)=3400/4=850`

Variance is given by `(Sigmax^2)/N-((Sigmax)/N)^2`

`(Sigmax^2)/N=1/4(1000^2+600^2+800^2+1000^2)`

= `1/4(1000000+360000+640000+1000000)=300000/4=750000`

Hence variance is `750000-(850)^2= 750000-722500=27500`