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Published online by Cambridge University Press: 01 January 2025
It is shown that in certain cases practice data approximately meet the assumptions involved in Thurstone's method of absolute scaling. An application of the method was accordingly made in the case of four test performances practiced for 39 days by a group of 56 subjects. The manner in which the practice data were scaled is described by using the data on practice in anagrams as an illustration. Scaling had little effect upon the correlations between initial and final score, but produced marked changes in the apparent effect of practice upon individual differences and in the correlations between initial score and gain.
This is one of a series of studies of the application of scaling methods to problems of experimental psychology in which the data are obtained from but a single group of subjects. For other studies, see (4), (5), (6), and (8).