In certain investigations involving an experimental group and a control group, the effect of the experimental treatment may be expected to manifest itself by increasing the scores of some subjects but by decreasing the scores of other subjects. Examples arise in the area of defensive behavior. Customary tests of differences between means are inappropriate for assessing the existence of effect of the experimental treatment in such cases. A test based on the ranks of the observations is proposed; it will be sensitive to extreme scores (either large or small or both) for experimentals.

Thurstone's multiple group method of factor analysis has been widely used as a basis for rotation to simple structure. To make the most of the economy offered by this method, factor axes may be located directly by the correlation clusters; and methods of doing this are here discussed.

The personnel-classification problems considered in this paper are related to those studied by Brogden (2), Lord (6), and Thorndike (8). Section 1 gives an approach to personnel classification. A basic problem and variations of it are treated in section 2; and the computation of a solution is illustrated in section 3. Two extensions of the basic problem are presented in section 4. Most of the methods indicated for computing solutions are applications of the “simplex” method used in linear programming (see 1, Chs. XXII, XXIII). The capabilities of a high speed computer in regard to the simplex method are discussed briefly (see section 1).

Twenty-five group tests, assembled with certain hypotheses concerning the first and second closure factors in mind, were administered to 154 subjects, mostly graduate students. The intercorrelations were analyzed factorially, yielding eight factors that were rotated to an oblique simple structure. The factors were interpreted as: speed of closure, C1; flexibility of closure, C2; verbal closure, C3; word fluency, W; reasoning, R; perceptual speed, P; the first space factor, S1; and speed of handwriting, H. Four second-order factors were tentatively described as analytical ability, synthetic ability, speed of perception, and word fluency. Three of the reasoning tests had their highest loadings on C2 and one on C3, which seems to be evidence that flexibility of closure generalizes in the cognitive domain and is associated with analytical ability.

This paper provides the formulas necessary for testing the significance of the differences between mean values of different multivariate normal populations by Hotelling's generalization of “Student'” ratio. It also indicates the methods, proposed by Mahalanobis, and by Rao, of classifying different multivariate populations and individuals. The methods are illustrated by means of personality test data obtained from students preparing for the General Elementary and the General Secondary Teaching Credentials.

A solution is developed in implicit form for the problem of assigning N men to n jobs, the proportion of men to be assigned to each job being specified in advance.

The rolling totals method of computing sums, sums of squares, and sums of cross-products appears to have several advantages over usual methods, in that it saves time and requires less equipment. Only an IBM sorter and a tabulator equipped with Card Cycle Total Transfer Device are used. The method provides an immediate independent visual check on the accuracy of the sums of cross-products of each successive variable as it is run. Since controlling is done by sorting, the necessity for re-wiring after each run on the tabulator is eliminated. The wiring, illustrated by a diagram, is simple and straightforward.

A table of values of Chi-square for two degrees of freedom corresponding to values of P from .001 to .999 is presented, together with a description and an example of its use in combining probabilities from two or more independent samples to obtain an aggregate probability.

A quick approximation of the best-fitting orthogonal simple structure from the known oblique simple structure is here developed.

The purpose of this article is to present a set of nomographs for testing the significance of the difference between uncorrelated percentages, and for determining necessary sample sizes when planning studies which will involve the comparison of percentages. Examples of these two uses are given as well as a description of the formula upon which the nomographs are based.

Test battery selection is justified on the grounds that it is more efficient than the conventional methods. More precise definitions of efficiency have shown that the additional cost of test administration can often outweigh the gains of selecting a more competent group of persons. Final evaluation of the profit and loss account can be made only when no further economies can be effected in the selection procedures themselves. A psychometric pre-screening technique which will reduce this cost considerably is developed here. Its psychometric structure is mathematically defined, and its advantages illustrated in terms of testing economy (E) and losses (L) of good material for different selection ratios (S.R.). It is shown that, under many circumstances, the testing economy can be considerable, and that in all practical cases “Losses” will be ≤ 1.5% for all values of ρ ≥ .8 (between the pre-screening test and the final battery). The technique in practice is illustrated from a set of data.

Scores on five differently speeded parts of a nonverbal reasoning test were analyzed to determine the relationship between the abilities measured by the speeded and the unspeeded parts. Two orthogonal factors were found: One is described as the ability to answer the problems correctly; the other is described as the tendency to answer the problems quickly. The first factor was found to be somewhat more valid than the second for predicting grades at the U. S. Naval Academy. The suggestion is made that descriptions of tests are incomplete unless they include some specification describing the speededness of the test.