Volume 1

Manual of mental and physical tests : a book of directions compiled with special reference to the experimental study of school children in the laboratory or classroom / by Guy Montrose Whipple.

  • Whipple, Guy Montrose, 1876-1941.
Date:
1914-1915
Catalogue details

Licence: In copyright

Credit: Manual of mental and physical tests : a book of directions compiled with special reference to the experimental study of school children in the laboratory or classroom / by Guy Montrose Whipple. Source: Wellcome Collection.

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    be determined: in short series it is not even necessary to ar¬ range the measures serially, as one-half of the measurements may be checked off by inspection. Its primary disadvantage is that it gives little weight to extreme deviations and may fail entirely to represent the type, yet, in many psychological ob¬ servations, it is precisely these extreme deviations which are most suspicious, so that this tendency of the median to lessen the significance of extreme measures may prove a positive advantage. In general, the longer the series or the more symmetrical the distribution of its values, the more nearly does the median approximate the mean. 3. The Mode If a number of measurements are distributed in ascending or descending order, a mode is a measure that appears more fre¬ quently than do measures just above or below it in the series. There may be several modes in a distribution, though usually there is but one, and we may then define the mode as the commonest single value, or the commonest condition. Many statistical arrays find a better representative value in the mode than in the average. Thus, when we speak of the “average American citizen/’ we really have in mind the typical citizen, the one most frequently met with. To borrow an illus¬ tration from Rietz (6, p. 684) : “If a community has 10 mil¬ lionaires, but all the other citizens are in poverty, an arith¬ metical average might give the impression that the people of the community are in good financial condition, while really the ‘average citizen' is in povert}T.” The primary use of the mode is, therefore, to characterize a type. Strictly speaking, we may have an empirical mode, as indi¬ cated in a given array, and a theoretical mode, which would be the most frequent condition in a theoretical distribution. The latter is difficult to compute and not often employed. If an array is very irregular, there is, in strictness, no mode or type at all, or at least the indicated mode has little significance.