They might have slightly different densities, slightly different shapes, depending on how they get packed into this volume. So there is some variation, which we can measure with standard deviation. So the standard deviation, let's just say for the sake of argument, for the random variable X, is 0.8 ounces. And just to build our intuition a little bit later in this video, let's say that this, the random variable X, is always stays constrained within a range. That if it goes above a certain weight or below a certain weight, then the company that produces it just throws out that box. And so let's say that our random variable X is always greater than or equal to 15 ounces, and it is always less than or equal to 17 ounces, just for argument. This will help us build our intuition later on.