Some proportion of the total teachers think that it is a good learning tool. That proportion is P. The rest of them think it's a bad learning tool. 1 minus P. We have a Bernoulli distribution right over here. We know that the mean of this distribution, or the expected value of this distribution, is actually going to be P. It's actually going to be a value. It's neither 0 or 1, so not an actual value that you could actually get out of a teacher if you were to ask them. They cannot say something in between good and not good, but the actual expected value is something in between. It is P. What we do is, we're taking a sample of those 250 teachers, and we got that 142 felt that computers were an essential teaching tool.