C. D. Fawcett 
Diagram XII. Second Cephalic Index, HjL. 
453 
4lO 
Index. 
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Professor Weldon having urged the importance of comparing the actual good- 
ness of fit of the skew and normal curves in at least one instance, we selected the 
breadth of the skull as an illustration, because this is a measurement, which, 
owing to the peaks of its curves, has already been used as an argument for racial 
mixture in the Naqada material. The female data (broken line, Diagram II., 
p. 445) provide a "mountain range" which many non-statistically trained cranio- 
logists would at once interpret as signifying racial mixture. Let us examine 
these data from the mathematical standpoint. The equation to the normal curve 
is: 2/ = 15-829 the origin being at 131-56 mm. and the standard devia- 
tion being 4-5618 ram. The equation to. the skew curve is given at the foot of 
the diagram, p. 445. The following are the observed and calculated frequencies : 
!/ = -01954 cos*''^''*-''^6i ^31 1859^ .r= 19-632 tan 9. 
Origin, 64-20. 
/ X Xl-t-tOl/ X \ 32-390 
. = 21-39(1 + —^^) (1-35:^) . 
Origin, 72-96. 
