00:01
You know, this problem we've been given the following probability distribution, and we would like to find the marginal distribution.
00:06
Now, to find the marginal distribution for x, we need to integrate out the y.
00:12
So we integrate out from 0 to 1, x plus y, dy.
00:18
And so this gives us x, y plus 1⁄2, y squared, evaluated from y is 0 to 1.
00:27
And so this is x plus 1⁄2.
00:34
And so our marginal distribution for x is x plus 1⁄2.
00:38
Half with x going from zero now for marginal distribution for y notice that this is just going to be the exact same thing because you do the exact same integral and so similarly we have f of y is y plus a half now in b we want to find the probability that x is bigger than 0 .25 and y is greater than a half and so here we need to integrate x goes from 0 to 0 .25 and y will then go from i'm sorry, x goes from 0 .25 to 1.
01:24
We have an upper bound of 1, so 0 .25 to 1.
01:29
And y goes from 0 .5 to 1 of x plus y, d .y.
01:36
I'm sorry, dx and then dy.
01:41
And so integrating with respect to x first, this is the integral from 0 .5 to 1 of 1 half x squared plus xy evaluated from x is 0 .25 to 1, d .y...