SEMAINE D'ÉTUDE SUR LE ROLE DE L ANALYSE ECONOMETRIQUE ETC. 
oc. 
The Sign of the w_ 
The w,_, may be positive or negative. However, to sim- 
plify the exposition, the following discussion will be limited tc 
the case in which they are positive. It will be seen, however, 
that the majority of the results which will be derived, in par- 
ticular those concerning the order of magnitude of the para- 
meters T, ©, and 4, hold in the general case where some 
coefficient have a negative value. 
Expression for :. 
SU 4 
511. In the same w-- 
(SII-T) 
vy 
= 
we have from _ _. 
T1] 
vo 
1] — 1 
whoa 
- 
WT 
AY 
with 
511-2) 
Ge 
Finally, from the general formula 
\ 
+ 
we have 
(511-3, 
Allais - pag. 200