mad

 MAD estimates the Mean Absolute deviation
 (note that according to [1,2] this is the mean deviation; 
 not the mean absolute deviation)

 y = mad(x,DIM)
   calculates the mean deviation of x in dimension DIM

 DIM    dimension
    1: STATS of columns
    2: STATS of rows
    default or []: first DIMENSION, with more than 1 element

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

 see also: SUMSKIPNAN, VAR, STD,

 REFERENCE(S):
 [1] http://mathworld.wolfram.com/MeanDeviation.html
 [2] L. Sachs, "Applied Statistics: A Handbook of Techniques", Springer-Verlag, 1984, page 253.

 [3] http://mathworld.wolfram.com/MeanAbsoluteDeviation.html
 [4] Kenney, J. F. and Keeping, E. S. "Mean Absolute Deviation." �6.4 in Mathematics of Statistics, Pt. 1, 3rd ed. Princeton, NJ: Van Nostrand, pp. 76-77 1962.