N number of values la ensemble average 



P( I ) conditional probability distribution function 



P power 



r final residuals In least squares technique 



RMS root mean square 



s spatial frequency 



u mean level of a(6) 



V amplitude of cosine component of a(9) 



Var variance of random distribution 



X general Independent variable 



X random variable 



X^ observation 1 



X statistical mean of random variable X 



7 general dependent variable 



a scaling factor 



e residual error 



Y(k) autocovarlance as a function of lag 



X spatial wavelength 



