# Math Help - variance

1. ## variance

The random variable X takes on the values 5, 20, 30, and 200
with probabilites 0.60, 0.30, 0.08, and 0.02 respectively.
find the VARIANCE of the random
variable X..

2. Originally Posted by ballin_sensation
The random variable X takes on the values 5, 20, 30, and 200
with probabilites 0.60, 0.30, 0.08, and 0.02 respectively.
find the VARIANCE of the random
variable X..
$V=E((X-\overline{X})^2)=\sum_{i=1}^4 (x_i-\overline{X})^2\;p(x_i)$

$\overline{X}=E(X)=\sum_{i=1}^4 x_i\;p(x_i)$

So now you can either do this or you have a problem in doing the above, if so tell us and we will try to sort out you problem.

CB