00:01
So in this question we have a density function, f of x, is 2x, whenever x is between 0 and 1 inclusive.
00:11
So let's find the expectation value of x.
00:14
The expected value of x is the integral from 0 to 1, x f f of x the x.
00:20
So that's the integral from 0 to 1 of 2x squared with respect to x.
00:26
So that gives us 2 thirds x cubed, evaluated between 0 and 1.
00:32
And this just gives us two thirds because at 1 x cubed is 1 and at 0 it's 0.
00:38
So the expected value of x is 2 thirds.
00:44
Now let's have a look at the expected value of x squared.
00:48
The expected value of x squared, sorry, that should be in here, is the integral from 0 to 1 of x squared, f of x d x, which is the integral from 0 to 1 of 2x cubed d x...