On testing hypotheses regarding a class of covariance structures

Let x be ap-component random variable having a multivariate normal distribution with covariance matrix . In this paper, we consider the problem of testing hypotheses of the formH ₀: =b ₁₁ + +b _{m m} , whereb _i 's are unknown scalars, and _i 's are a set of known and simultaneously diagonalizable matrices. This problem has both psychometric and statistical interest, and its basic theory is developed here. Besides, the problem of obtaining likelihood-ratio statistic for testingH ₀ is studied, and the statistic obtained in a special case.     

The minimal transformation to orthonormality

The solution is presented to the problem of finding that orthonormal matrix closest in the least-square sense to a given matrix of full rank. An application is shown to the problem in multiple regression analysis of determining the importance of each independent variable.     

NOTE ON THE DOUBLE CENTERING OF DICHOTOMIZED MATRICES

A method is described for the double centering of dichotomized score matrices. It is based on a modification of the r _s coefficient of Guilford in which a second set of values, based on the reversed scoring of the original set, is used. A comparison of indices from matrices centered in such a manner, with some coefficients customarily obtained from score matrices, is presented.     

Interference with memory for lifted weight

An adaptation-level model for memory was tested by interpolating different weights between the standard and comparison weights. The results suggest that the model should be modified to account for the general tendency to use alternative categories of judgment with equal frequency. In terms of the modified model, memory for the standard shifts toward the value of the interfering stimulus, the magnitude of shift being proportional to the difference between the interfering stimulus and the value the memory would otherwise have had.     

The role of stimulation in the delay of onset of crying in the newborn infant

Crying is said to result from stimulus need. An experiment was done in which infants were stimulated during quiet periods to see if this would postpone the onset of crying. The results were positive. An alternative explanation in terms of internal temperature control is considered.     

Clinical application of conditioning and other behavioral techniques: Conceptual and professional considerations

It is only recently that conditioning and allied techniques have been applied on any large scale outside the laboratory. With the emergence of these procedures into the clinical world, in particular, a new class of problems present themselves. It is no longer sufficient to focus upon narrowly technical or theoretical problems; philosophies, social and practical issues must be taken into consideration and the new techniques evaluated conceptually and practically in direct comparison with their psychodynamic alternatives. Selected issues are presented and discussed.