00:02
So in this case, our random variable x is binomial, with the number of trials is 10, so our sample size is just 10, and our probability of success is 0 .67, where we define success as the home mortgage being current.
00:19
So that is our probability of success, and 0 .67 is straight from the problem.
00:25
So for part a, we're supposed to calculate the probability that x is exactly 4, where we have four successes in our sample side, in our sample.
00:38
So let's do that.
00:39
We can calculate the probability that is x is equal to 4.
00:43
We can use a formula that's directly above.
00:45
So we use a combination of and choose x.
00:47
So in this case, we would be 10 choose 4.
00:50
And probability of success is 0 .67, raise to the power of...