Second, at least 5 percent of the volume of sales to the allegedly targeted group must be at prices that are lower than the average price of the lowest-priced non-targeted group by a margin (a gap) that is greater than the averagegap between the average prices of all the non-targeted groups.
Private school students do better on the National Assessment of Educational Progress, but the gap between average scores is about the same at ages 13 and 17 as at 9.