ABSTRACT
As a southerner who has spent much of his life in the north I know that some northerners tend to think of southerners as unmotivated, ignorant, slipshod, or lazy. And some southerners tend to think of northerners as rude, boorish, overaggressive, and generally unpleasant. Northerners like to think of themselves as efficient and businesslike, while southerners like to see themselves as polite and gracious. These extreme images become much less intense when people migrate and intermix and get to know more individuals of the opposite group. Experience with people always shows that there is great variation within any group even if the group appears to be homogeneous to outsiders. (Statisticians commonly shorten the phrase "variation within a group" to "within variation. '')
After we have learned that there is within variation (some geniuses are much smarter than others) it is a mistake to conclude that variation between groups doesn't exist. Experience in experimental science teaches that whether we're dealing with people, animals, plants, metal bars, or batches of chemical, if two groups are identifiable as different there will be differences between them in every measurable characteristic. If we could measure efficiency and graciousness, we might indeed find that northerners are on the average a little more efficient than southerners and that southerners are on the average a little more gracious than northerners. These "between differences" (differences between the group averages)
may be small compared to some of the "within differences," but if they were not there at all one might wonder where the images originated, and why it is that they seem to prevail with minor modifications in other countries. (It could be strictly a reaction to climate, and I've often intended to ask my Australian friends if the phenomenon is seen in reverse in that global control group of the other hemisphere.)
The within-vs.-between question pops up frequently in everyday life. There we often can't apply the numerical methods of statistics to it, but many discussions can be clarified by use of the terms "within variation" and "between variation."
