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A SIMPLE METHOD OF CALCULATING THE COEFFICIENT OF CORRELATION
Author(s) -
WOLFE JACK M.
Publication year - 1971
Publication title -
journal of educational measurement
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.917
H-Index - 47
eISSN - 1745-3984
pISSN - 0022-0655
DOI - 10.1111/j.1745-3984.1971.tb00929.x
Subject(s) - mathematics , diagonal , statistics , correlation coefficient , moment (physics) , correlation , value (mathematics) , fisher transformation , table (database) , simple (philosophy) , combinatorics , geometry , physics , philosophy , epistemology , computer science , data mining , classical mechanics
Where two sets of measurements can each be grouped into below average, average and above average classifications with an equal number assigned to each of the below average and above average classifications, a 3 by 3 table can then be tabulated with frequency counts. The exact value of the product moment coefficient of correlation can then be calculated very simply by means of the formula, r = (DIFF)/2m, where DIFF is the difference between the sum of the corner numbers on the positive diagonal and the sum of the corner numbers on the negative diagonal, and m equals the number in each of the below average and above average classifications for each variable. The formula for r is applicable to negative as well as positive correlation.