00:01
Here we have this joint pmf, random variables, x and y.
00:04
And the y are these values here.
00:07
Actually, these values here.
00:09
They're both one to three.
00:10
Then here we have the joint distribution table.
00:12
3c for 1 -1, 2c for 2 -1, 2 -1, c for 2 -1, c for 2 -1, so on and so forth.
00:17
And the first part of this task asks us to find the constant c.
00:22
So the way we do this is we, well, the joint distribution should all sum to one.
00:26
So basically what we do is we add up all these values, 3c, plus.
00:30
Let me just kind of make this a little quicker for us.
00:32
3 plus 2 plus 1 is 6c.
00:36
C and c give us 2c, and then 6c, 4c and 2c is 12c.
00:42
You add these up.
00:45
It gives us 20c, and this should equal 1.
00:49
So 20c should equal 1 because the distribution is to summed 1.
00:53
That tells us c is 1 .20th.
00:56
Now to figure out the distribution table, we substitute 120th and for c.
01:03
And then we can get our distribution table here.
01:06
So we figured the c out.
01:09
So this is our new distribution.
01:10
0 .15 is equal to 3 over 20.
01:12
So anyway, that's what you do.
01:14
6 over 20 is 0 .3, 4 over 20 is 0 .2.
01:17
And you can see the whole table here...