So essentially we want a z value where the entire percentage below it is going to be 97.5%, because then you're going to have 2.5% over here. And we've actually already figured that out. This whole cumulative has to be 97.5%. We did that in the last video. If you look for that, you get 97.975 right there. It's a z-score of 1.96. I even wrote it over there.