If X is normally distributed, we could write that X is a normal random variable with a mean of 0 and a variance of 1. Or you could say that the expected value of X is equal to 0, or in that the variance of our random variable X is equal to 1. Or just to visualize it, is that we're sampling, when we take an instantiation of this variable, we're sampling from a normal distribution, a standardized normal distribution that looks like this. Mean of 0, and then a variance of 1, which would also mean, of course, a standard deviation of 1. So that could be the standard deviation, or the variance, or the standard deviation, that would be equal to 1. So a chi-squared distribution, if you just take one of these random variables, and let me define it this way. Let me define a new random variable, q, that is equal to you essentially sampling from this standard normal distribution, and then squaring whatever number you got.