116 STATISTICAL METHODS. 



I. FORMULAS. 



= 0.6745^=. x = V-J. 

 \/n 



= 0.6745-^, 



V2n 



C=j-XlOO%. E, 



A. D.=^^ = 0.7979(7. ^ =0.6745(7. 



1 I 



(* 4 ./) , j ^(rr 2 ./) , 7 j. 

 71^^2/1 ^240 J * 



|f (Types I, IV). a = 2Vp 3 (Type y)> 



Probable discrepancy, ^' \ . ( -^ } - A+^ I * 

 Vn / 2 2/ \ J 7 ) 



J(dev. rcXdev. yX/) = S(x& 2 f) _ 0.6745(1 -r 2 ) 



(72 

 ro (spurious correlation) = 



. 



71 o 2 n 



To solve any equation of the second degree, 



-b\/b 2 -4ac 

 Q; x= =~ . 



