So our standard deviation is equal to, and we have proved this in other videos, it's equal to the square root of N times P times one minus P. Notice, you just put an N right over here under the radical sign, and so this is going to get us, in this particular situation, to 10 times 0.6 times 0.4, and then the square root of everything. So all of this is review. If it's unfamiliar, I encourage you to review some of the videos on Bernoulli random variables and on binomial random variables. But what we're going to do in this video is think about a sampling distribution, and it's going to be the sampling distribution for a sample statistic known as the sample proportion, which we actually talked about when we first introduced sampling distributions. So let's say, so let's just park all of this. This is background right over here. Let's start taking samples of 10, and I didn't pick that randomly.