ds_list_vmr
In probability theory and statistics, the variance-to-mean ratio (VMR), like the coefficient of variation, is a normalized measure of the dispersion of a probability distribution: it is a measure used to quantify whether a set of observed occurrences are clustered or dispersed compared to a standard statistical model.
It is defined as the ratio of the variance \(\sigma^2\) to the mean \(\mu\),
\( \large D = {\sigma^2 \over \mu } \).
- ds_list_vmr(id [,sample])
- Returns the variance-to-mean ratio of the values in a given list.
COPY/// ds_list_vmr(id [,sample])
//
// Returns the variance-to-mean ratio of the values in a given list.
//
// id list data structure, real
// sample true if the list is made up of a sample, bool
//
/// gmlscripts.pro/license
{
var n, avg, sum, i;
n = ds_list_size(argument0);
avg = 0;
sum = 0;
for (i=0; i<n; i+=1) avg += ds_list_find_value(argument0, i);
avg /= n;
for (i=0; i<n; i+=1) sum += sqr(ds_list_find_value(argument0, i) - avg);
return sum/(n - argument1)/avg;
}
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