APPENDIX I. 

 Example of the Computation of a Correlation. 



Correlation between 'class-place' (a?) and a teacher's estimate of 

 intelligence (y). 



62 (a VY 

 Index of correlation = Q = 1 -- . 



n n 



Probable error = P. JE7. = .706 



(n 23 pupils in Untertertia grade entered at about 12 years.) 



Pupils x y x y (x y)* 



A 1 10 9 81 



B 2 14 12 144 



C 3 13 10 100 



D 4 1 +3 9 



E 5 5 00 



F 6 7 1 1 



G 7 20 13 169 



H 8 2 +6 36 



I 9 8 +1 1 



J 10 15 5 25 



K 11 9 +2 4 



L 12 22 10 100 



M 13 4 +9 81 



N 14 11 + 3 9 



O 15 3 +12 144 



P 16 21 5 25 



Q 17 6 +11 121 



R 18 18 00 



S 19 12 +7 49 



T 20 16 +4 16 



U 21 23 2 4 



V 22 17 +5 25 



W 23 19 +4 16 



6 . 1160 



_1 =0.43. 



23 (23 2 1) 



1_0.43 2 



Sum 1160 



