So let's figure out the z-scores for each of these scores. So 65, or each of these grades. 65 is how far? 65 is, you know, it's maybe going to be here someplace. So we first want to say, well, how far is it just from our mean, from our mean? So the distance is, we just want a positive number here. Well, actually, you want a negative number, because you want your z-score to be positive or negative.