And we know a lot about the sampling distribution of the sample proportions. We know already, for example, and if this is foreign to you, I encourage you to watch the videos on this on Khan Academy, that the mean of this sampling distribution is going to be the actual population proportion. And we also know what the standard deviation of this is going to be. So let me, that's maybe, that's one standard deviation, this is two standard deviations, that's three standard deviations. Above the mean, that's one standard deviation, two standard deviations, three standard deviations below the mean. So this distance, let me do this in a different color. This standard deviation right over here, which we denote as the standard deviation of the sample proportions for this sampling distribution.