And so this is the expression, or square that quantity. And so this is the expression for the variance of y, and we can simplify it a little bit. So this is all going to be equal to, so let me just, p times one minus p squared. And then this is just going to be p squared times one minus p, plus p squared times one minus p. And let's see, we can factor out a p times one minus p. So what is that going to be left with? So if we factor out a p times one minus p here, we're just going to be left with a one minus p. And if we factor out a p times one minus p here, we're just going to have a plus p. These two cancel out. This is just, this whole thing is just a one. So you're left with p times one minus p, which is indeed the variance for a binomial variable.