00:01
So we want to distinguish between some different types of probabilities.
00:03
And let's just make a little chart here.
00:05
Sorry, this doesn't look also great.
00:07
Here's a1 and a2.
00:10
And here's b1 and b2.
00:14
So say that this is color of hair and you're either a1 or a2.
00:20
And let's say this is color of skin.
00:22
And you're either b1 or b2.
00:24
And so here would be our probabilities and this is a and this is b and this is b.
00:30
C and this is d.
00:32
And all of these little a, b, c, d are all joint probabilities.
00:41
And they're actually the intersections.
00:44
They're intersections.
00:49
Now we have some other probabilities.
00:52
And if we add these two together, a plus b, and we add these two together, c plus d.
00:59
Add these two together, a plus c, and add these two together, b plus d.
01:06
All of these red ones are marginal probabilities.
01:11
They're row probabilities or column probabilities...