And the standard deviation, this comes straight from the central limit theorem. So the standard deviation of our sample proportions is going to be the square root. It's going to be our population standard deviation. The standard deviation we're assuming with our null hypothesis divided by the square root of the number of samples we have. And in this case, we have 150 samples. It's going to be 150 samples, and we can calculate this. This value on top, we just figured out, is the square root of 0.21.