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nents f;(#) and with residuals v, independently and normally 
distributed, the TANUS quotient (75) is distributed as 
m—r 
(81) 
Here the ¥2-variates are independent w 
indicated within paranthesis: x. 
squation 
.u degrees of freedorr 
are the roots ol 
det (C. 2C,—U 
where C is the product sum matrix 
« 
Wliüil 
and C, is the corresponding product sum matrix for the pre- 
diction range. It will be noted from (81) that the JANUS quo- 
tient tends to increase with the prediction span and with the 
number of free parameters. 
2) Forecasting by the chain brincible 
We shall consider the case of a stationary unirelation mo- 
del M which we specify bv the representation 
(82a-b) 
* 
5 - Br V1 +Ba V2 + 
«Ly U t 1, +X, v, , = 
[2] Wold - pag. 43