We just said if this thing is well over 30, or at least 30, then this value right here, this statistic, is going to be normally distributed. If it's not, if this is small, then this is going to have a t distribution. And then you're going to do the exact same thing you did here, but now you would assume that the bell is no longer a normal distribution. So in this example, it was normal. All of the z's are normally distributed. Over here in a t distribution, and this will actually be a normalized t distribution right here, because we subtracted out the mean. So in a normalized t distribution, you're going to have a mean of 0.