Re: mode?

From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>
Date: Mon, 3 Apr 2006 12:03:03 -0600 (MDT)

>Is there an easy way to compute mode (statistic) in NCL?
>It would be nice if there was a dim_mode function.
>For example, if I have a variable var(lat,lon,time), how can
>I get the mode for each grid point (mode(lat,lon))?
Conceptually easy .... Not so, in practice,
See Numerical Recipies "Estimation of the Mode ..."

Are the data guaranteed to be unimodal?
What to do if you have bimodal data?

"An interesting empirical relationship between 
 the mean, median, and mode which appears to hold 
 for unimodal curves of moderate asymmetry is given by
mean-mode = [approx] 3(mean-median)"  
Hence, mode = mean - 3(mean-median) 
   mean   = dim_avg_Wrap(..)
   median = dim_median(..) 
   mode   = mean              ; transfer meta data
   mode   = mean - 3*(mean-median)
   mode_at_long_name = "mode [approximate]"
   mode@info      = ""
   mode_at_equation  = "mean - 3*(mean-median)"
Good luck
ncl-talk mailing list
Received on Mon Apr 03 2006 - 12:03:03 MDT

This archive was generated by hypermail 2.2.0 : Tue Apr 04 2006 - 11:27:39 MDT