Before evaluating the performance of the beta-binomial kriging model, some properties
of the spatial relationship of the observed sample proportions Zi
ni should be established.
No additional variability is added to the model during the transformation from a Gaussian
random field to a beta random field, since these are two smooth continuous distributions.
So therefore, any additional variability in the nugget effect must occur at the binomial
proportion level.
For constant sample size n at each spatial location, the relationship between variance
of the latent beta random field V ar(Y ) and the variance of the beta-binomial sample proportions
V ar 4 Z
n
5
is straightforward to show. The variance of a beta distribution is defined