quartile

As a result, just three percent of students at the most selective 200 colleges represent the bottom income quartile.

In fact, the median passing mark in our 17-game 2010s would have been 4,003 yards — not just above the third quartile of what we’re used to, but a mark that passers for two NFL franchises never reached in the entire 16-game era.

Of course, that's just an illustration; people don't mechanically drop down a quartile by getting more education.

A 3rd quartile candidate with "some college"earning $1085 a week becomes a second-quartile BA holder earning . . . $1066.

The upper quartile or group will now contain that fourth of the class whose grades were highest.

First Quartile--Fairly clear; illumination of actual scene is fairly represented.