Well, it turns out that you can't just add up the standard deviations, but you can add up the variances. So it is the case that the variance of X plus Y is equal to the variance of X plus the variance of Y. And so this is gonna have an X right over here, X, and then we have plus Y and our Y. And actually, both of these assume independent random variables. So it assumes X and Y are independent. I'm gonna write it in caps. In a future video, I'm going to give you, hopefully, a better intuition for why this must be true, that they're independent, in order to make this claim right over here.