Because a lot of z tables will actually do something like this. For a given z, they'll say, what is the total area going all the way from negative infinity up to including z standard deviations above the mean? So when you look up a lot of z tables, they will give you this area. So one way to think about this, we wanna find the critical value, we wanna find the z that leaves not 6% unshaded in, but leaves 3% unshaded in. Where did I get that from? Well, 100% minus 94% is 6%. But remember, this is going to be symmetric on the left and the right.