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Prof. Karl Pearson. 



7. Taking 205 marriages in which I had details of the stature of 

 husbands and wives and the size of their families, two correlation tables 

 were formed (i) for husbands and wives, as such, (ii) for fathers and 

 mothers, i.e.^ for husbands and wives weighted wdth their fertility. 

 The tabulation and calculations for (ii) are due to Mr. L. Bramley- 

 Moore, with the assistance of Mr. K. Tressler. For (i) I had worked 

 •out the data some years ago myself. The following results were 

 obtained : — 



VIII. — Correlation between between Statures of Husband and AVif e. 





!N"o. of cases. 



Value of correlation. 



Husband and wife. . . . 

 Father and motker . . . 



205 

 965 



0-0931 ± 0-0467 

 0-1783 ± 0-0210 



Now these results seem at first sight significant. We have practically 

 doubled the intensity of assortative mating by weighting the observa- 

 1)ions with fertility. Fertility would thus not be distributed at random, 

 but would increase with the amount of homogamy. The process of 

 -collecting the original data here conceived was totally different from 

 that of my own family data cards, the influence of size of family on 

 chance of procuring data being I consider nothing like as marked.* 

 This is, I think, the source of the difi'erence in correlation of stature 

 between husband and wife being so reduced. 



8. In order to further investigate the matter directly, a correlation 

 table was prepared for me by Mr. L. Bramley-Moore, in which the 

 variables were (i) difference in stature of husbands and wives, and (ii) 

 size of family. In this case the statures of the wives were reduced to 

 male equivalents before the difference was taken, f Thus the difference 

 is zero, w^hen the wife has the female stature which corresponds to her 

 husband's. The calculations on this table were made by Miss Alice 

 Lee, D.Sc. The correlation was found to be negative, and its value 



-0-1201 ±0-0464 



Thus it would seem that large difference in stature means small 

 fertility. But there is danger of a fallacy here, which requires careful 

 investigation. The regression equation for size of family ( /") in terms 

 of difference of stature of husband and wife in inches {d) is 



* ' Phil. Trans.,' A, vol. 187, p. 269. They were not a selection of families by size, 

 but rather by the existence of fairly complete ancestral records. 



t The ratio of n.ean statures — I'OS about, and was added to the female 

 stature to convert it into its male equivalent. 



