[R] Measuring dispersion

Jim Lemon
Tue, 17 Jun 2008 11:45:25 -0000

S. Nunes wrote:
> Hi,
>
> I'm looking for a function to measure the dispersion of a set of
> values ranging from 0 to 1.
> This function should be 0 if all the values are evenly spaced within
> the interval and it should be > 0 if values are clustered.
> The more clustered the values are, the higher should the function be.
>
> An example:
>
> [0; 0.2; 0.4; 0.6; 0.8; 1] - function should be ~ 0
> [0; 0.1; 0.1; 0.15; 1] - function should be > 1
>
> This data comes from time-dependent observations recorded between a
> start time (0) and an end time (1).
> I want to find out which series are more clustered, i.e. less evenly
> distributed.
>
> I'm going to test Kurtosis for this but it doesn't seem to be the
best
> tool for the job.
> As I understand, Kurtosis evaluates the "strength" of a single
central
> peak. My data can have multiple peaks (clusters).
>
Hi Sergio,
It sounds like what you want is the negative of the entropy. I'm not
sure if there is a readymade function to calculate this, but someone
else on the list might know.

Jim