00:01
So we're letting x equal the number of heads when we toss a coin four times.
00:09
And we not want the probability distribution for that.
00:13
And so we could have no heads, one head, two heads, three heads, four heads.
00:19
And we know that there are two, two, two, two ways.
00:22
Two times two times two times two.
00:25
There are 16 different outcomes.
00:27
And we have one of them would be no heads out of 16.
00:32
And we know that there are, there's one way for them all to be four heads.
00:38
And so then we have to look at the different possibilities.
00:41
And to have one head, we could either have heads here, here, here, or here, and then the others being tail.
00:47
So there are four out of 16 here.
00:49
And likewise, there are four ways to have three heads in one tail...