Re: [ai-geostats] Re: descriptive statistics or inference?

2004-12-12 Thread Digby Millikan
Meng-ying, Sorry I don't have time to process the data yet, but a summary so far, is that geostatisitcs was originally developed in the mining field, and for the application of mineral resource assesment with which I am involved where sampling patterns are generally clustered and the use of the sil

[ai-geostats] Re: descriptive statistics or inference?

2004-12-12 Thread Isobel Clark
Digby The variance/sill relationship is theoretical and does not depend on the layout of the samples, regular or clustered. Since the sill only uses pairs where samples are uncorrelated from one another, the clustering is irrelevant. It does depend on the distribution of the samples values being

Re: [ai-geostats] Re: descriptive statistics or inference?

2004-12-12 Thread Meng-Ying Li
Like Isobel mentioned, the sill only uses pairs where samples are uncorrelated from one another, and in this case the clustering is irrelevant. And I totally agree with that. The crucial thing, Digby, is that you want to make sure the variance estimated reflects the characteristic of what you actu

Re: [ai-geostats] Re: descriptive statistics or inference?

2004-12-12 Thread Digby Millikan
Isobel, Thankyou, in relation to Colins work then the variance may be estimated from the sill of the variograms for the two orebodies and if the two orebodies had lognormal distributions, they may have a different mean and variance, but may still display the proportional effect, i.e. similar coeff