With that said, we’ll extend this idea a bit more. If the distribution of scores is normal, we can also say that between different points along the x-axis (such as between the mean and 1 standard deviation), a certain percentage of cases will fall. In fact, between the mean (which in this case is 100—got that yet?) and 1 standard deviation above the mean (which is 110), about 34% (actually 34.13%) of all cases in the distribution of scores will fall. That’s about a third of all scores. Because the normal curve is normal, this is true for going the other direction, too. About a third of all
...more
