As a matter of fact, college students are a selected group. If the surface A (Fig. 9) represents the distribution of all elementary school pupils at a given time, then most of those pupils who are to go to college fall in the upper end of that surface. If our colleges took the best students and only the best, if they made a clean cut off the top, then the distribution of their abilities would be represented by a surface closely approximating EFG of surface A. But for various reasons—including our extremely inaccurate means of attempting to determine fitness for entrance—our colleges do not admit merely those who are best fitted to pursue higher study, that is, the upper end of the
surface. Some pupils find ways into college who occupy stations in the surface not far above the median; or the line of mediocre ability. This is clearly shown in Professor Dearborn's study of the relative standing in scholarship of students in high school and in college. Consequently the lower end of the surface would not be clean-cut as in EFG, but rather like the heavy line of Fig. 10. It would, of course, be skewed positively, for there could not possibly be many cases near G. Most of them would have to fall in the larger space near EF. The curve would be similar to that for incomes. The heavy line in Fig. 10, therefore, though not representing with precision the scientifically correct distri-
- Thorndike, E. L., "The Selective Influence of the College," Educational Review, 30, 1.
- "The curve of probability gives us the only precise meaning of the term 'scientific knowledge.' We have seen that human observations and measurements are never precisely accurate. Generalizations, in like manner, are never precisely true. The formulation of a law of nature can never be made absolutely exact. Scientific knowledge, therefore, is not that absolutely exact and certain knowledge which the popular mind assumes it to be. It is certainty or exactness within a range of error, and to diminish that range is the object of scientific endeavor." Giddings, F. H., "Sociology," Columbia University Press, New York, 1908, p. 24.