Getting unexpected results when generating descriptive statistics for a column of Z scores

Hello, I am new to excel, so hopefully this is an obvious question with an easy fix. But I am getting some really weird results when trying to work with the z-scores that I generate for a data set. The formula I am using is =standardize(x,mean,stdev) where X is the cell number I am referring to. Then once executing that formula, I copy it and paste it down the column to get the Z scores for all 170 data points. When eyeballing those results, it looks right, but I’m getting unexpected results when I try to average them and get the new standard deviation. The formula I use for average is =average(b2:b172) and I am getting -4 point something. For standard deviation, I am using =stdev.p(b2:b172). I have also tried getting the sample standard deviation, stdev.s, and I am getting unexpected results. I expect my standard deviation to be around two.

I also have the data analysis pack enabled and tried generating descriptive statistics on the Z score column with the same results as with the formulas. I have tried calculating the Z score using the value for stdev.s and stdev.p, as well as the standard error that is generated by the descriptive statistics. Another thing to note is that there were two cells with a Null in them so I removed them from the column and adjusted my formulas accordingly. I am wondering if there is an error I’m making with one of my formulas or in working with my data, or maybe if I don’t fully understand what is needed to get Z scores. I am taking an online statistics class right now and trying to teach myself to use Excel in place of the software that is used for the class because I use a screen reader on my computer And the course software is not accessible with that so I am just trying to figure out how to do all of this. Any ideas of other things I could try would be helpful.