Find the mean and variance for each of the data in Question:

Explanation

Let assumed mean `A=20`
Mean `=A+(sumf_(i)d_(i))/(sumf_(i))=20+(-40)/40=20-1=19`
Variance `sigma^(2)=1/(N^(2))[Nsumf_(i)d_(i)^(2)-(sumf_(i)d_(i))^(2)]`
`=1/(40^(2))[40xx1776-(-40)^(2)]`
`=44.4 =1=43.4`