00:01
In this table we have the probability distribution for a discrete random variable x.
00:07
And for the first step, we're asked to find the expected value of x.
00:15
For any discrete random variable, the expected value is given by this formula.
00:21
It's the summation over all possible values of x of x times the probability of x.
00:28
So here that's 1 times 0 .1 plus 2 times 0 .2, plus 3 times 0 .3, and so on.
00:46
And this comes out to 3 .2.
00:50
And for the second step, we're asked to calculate the variance.
00:55
The variance for any discrete random variable is given by this formula.
01:00
See, that's sigma squared.
01:04
The summation over all possible values of the random variable of x minus the mean squared times the probability of x.
01:16
And this can be expressed also in this form.
01:29
Here, the mean is the expected value...