Karl Pearson and David Heron 
283 
(14) General Protest against the Use of Mr Yule's Coefficient of Association. 
It may be said that a vigorous protest against Mr Yule's coefficients is 
unnecessary. We believe on the contrary that, if not made now and made 
strongly, there will be a great set-back to both modern statistical theory and 
Diagram XXIII. Values of r t for a typical table of ordinary statistical practice. 
10 
10 20 30 40 5-0 60 70 
Percentage of total in smallest quadrant. 
80 
9 0 
modern statistical practice. The publication of Mr Yule's text-book has resusci- 
tated the use of his coefficient of association ; it is now being used in all sorts of 
quarters for all sorts of unsuitable data. The publication of Mr Yule's recent 
paper on Association will also lead to the use of his method of pseudo-ranks. The 
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