MEAN calculates the mean of data elements. 
 
  y = mean(x [,DIM] [,opt] [, W])

 DIM	dimension
	1 MEAN of columns
	2 MEAN of rows
 	N MEAN of  N-th dimension 
	default or []: first DIMENSION, with more than 1 element

 opt	options 
	'A' arithmetic mean
	'G' geometric mean
	'H' harmonic mean

 W	weights to compute weighted mean (default: [])
	if W=[], all weights are 1. 
	number of elements in W must match size(x,DIM) 

 usage: 
	mean(x)
	mean(x,DIM)
	mean(x,opt)
	mean(x,opt,DIM)
	mean(x,DIM,opt)
	mean(x,DIM,W)
	mean(x,DIM,opt,W); '

 features:
 - can deal with NaN's (missing values)
 - weighting of data 
 - dimension argument also in Octave
 - compatible to Matlab and Octave

 see also: SUMSKIPNAN, MEAN, GEOMEAN, HARMMEAN

Package: nan