And each of them are independent, standard, normally distributed random variables. Let me just remind you what that means. So let's say I have the random variable X. 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.