FUNCTION Function M-files.
 	New functions may be added to MATLAB's vocabulary if they
  	are expressed in terms of other existing functions. The 
  	commands and functions that comprise the new function must
  	be put in a file whose name defines the name of the new 
  	function, with a filename extension of '.m'. At the top of
 	the file must be a line that contains the syntax definition
 	for the new function. For example, the existence of a file 
 	on disk called STAT.M with:
  
  	        function [mean,stdev] = stat(x)
  	        n = length(x);
  	        mean = sum(x) / n;
  	        stdev = sqrt(sum((x - mean).^2)/n);
  
  	defines a new function called STAT that calculates the 
  	mean and standard deviation of a vector. The variables
  	within the body of the function are all local variables.
  	See SCRIPT for procedures that work globally on the work-
  	space. 
 
 	See also ECHO, SCRIPT.