The average "period" is estimated from a finite series of individual 

 "period" observations such that 



T = l/n ST.. (43) 



1 = 1 ' 



Now consider the following form which is always greater than or 



equal to zero because it is the integral of an always positive (or zero) 



function. 



GO 



(T-r)%(T) dT >0 (44) 



f. 



It yields 



® o -00 m 



/ T g(T)dT-2T/ Tg(T)dT + T / g (j) d T > 



, r CO 2 



T* = 1 T g(T)dT>T 



(46) 

 The term on the left is estimated by 



2 I —, 1^ ^ 



Now let L* be the average "wave length" computed by computing 

 the "wave length" associated with each of the observed "periods" 

 and averaging the results. From equation (47), this "wave length" 

 is given by 



i.2 n "^2 



L* --YV -- TT f„ -Yt- (48) 



The wave length, L computed from the average "period" is found by 

 averaging the observed "periods" and computing the average "wave 

 length" from the average "period" according to equation (43), 



r^ 



But from equation (46), L* is greater than L and from equation 



A, 



42 



