Karl Pearson 
245 
The following fourth order mean products are deduced from the more general 
values given by Isserlis * : 
in) 
(0) 
ip) 
(?) 
while 
(r) 
2 (8n5pS%j,8ng"j,8ng"j,) 
S {(8n,j,)2Sng'j,8vj>} 
V ivy iV V Nj' 
A 
= 'v(l-?f){3(l-|)"..(l-5f) + l 
is due to Pearson f. 
I shall now use (n.) to (r) to determine S (8«(j,)*/A to the first order terms. 
S (8n,j,)2 (8nyj,)2S/gg,2 
Substituting from {n)-{q) above we obtain the following result : 
S(8»g^ _ 1 
A n 
« 4 
J) L 
3(l4).l.,„(l-|-') + l)« 
1 r ^a- ' 
+ 6S 
- 12S 
+ 245 
N 
1 _ 1^ f'l ^J'\ 7. 2' 
V iV 
3)1 QTj, 'Ht^'j, "^q''^ 
iV2 
* i?. Proc. Vol. 92, A, pp. 28-29 (1916). 
t Phil. Trans. Vol. 186, A, p. 347 (1894). 
