Confident that the standard deviation of our sampling distribution is going to be around, instead of using this, we can use our standard deviation of our sample, our sample standard deviation. 0.50 divided by the square root of 250, and what's that going to be? That is going to be, so we have this value right over here, actually I don't have to round it, divided by the square root of 250. We get 0.031, so this is equal to 0.031 over here. That's one standard deviation. Now, they want a 99% confidence interval. The way I think about it is, if I randomly pick a sample from the sampling distribution, what's the 99% chance, or how many, let me think of it this way, how many standard deviations away from the mean do we have to be that we can be 99% confident that any sample from the sampling distribution will be in that interval?