My text book has the z-score table but it doesn't explain why the sign or magnitude means. It automatically assumes that we know. I tried searching for this information but i cant find it. 1. Explain why do normal score tables typically not include z values greater than 2.99. So can anyone give me the link to some sites that contain this type of information. 2. Explain why an outlier affects the mean more than the median or mode. Is it because the mean changes with the data. If you change some of the values then the mean will also change but the mode and median should remain roughly the same.