[gradsusr] coefficient of variation

[Jeff Duda]

The coefficient of variation is just a normalized standard deviation (std
dev / mean).  It's generally only meant to be applied to data sets that are
all of the same sign (all positive or all negative).  You can use the ave
or aave functions in Grads to compute the mean over some area or time
extent.  You can then use the mean to compute the spread using the popular
equation for standard deviation: std dev = sqrt(1/(N-1) *
sum[(x-ave(x))^2]).  That should be fairly easy for you to code up.  Do you
need help with the coding?

Jeff Duda

On Mon, Feb 6, 2012 at 9:18 AM, Ismaila Diallo <ismailadiallo64 at yahoo.fr>wrote:

> Hi,
>
> Does someone has a grads script which can calculate the coefficient of
> variation or  knows how to do it with grads.
>
> Thansk in advance
>
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>


-- 
Jeff Duda
Graduate research assistant
University of Oklahoma School of Meteorology
Center for Analysis and Prediction of Storms
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