Abstract
This paper explores the possibility of applying the mathematical techniques of the Discrete Fourier Transformation (DFT) to the estimation of the true work curve of the Uchida-Kraepelin psychodiagnostic test, which has been widely used in Japan. Section 1 reviews the mathematical model of the work curve which was proposed by Kashiwagi (1962) on the basis of the principle of mechanical or electric oscillation. Section 2 discusses from the mathematical viewpoint those aspects of DFT and of spectral density that are necessary in the present analysis. 3 numerical examples based on 220 cases obtained at Japanese National Railways are presented in Section 3, and it is shown that the DFT estimates yield perfect goodness of fit to the true values based on Kashiwagi's item-test least squares regressional estimation model. Related problems and suggested approaches are discussed in Section 4.
