There ws a pretty good paper on global standard errors in the 1984 APCOM proceedings, so I am sure it should be in the major textbooks by now.
Commparing the sills is very straightforward, I think. Isobel http://geecosse.bizland.com/books.htm --- Chaosheng Zhang <[EMAIL PROTECTED]> wrote: > Isobel, > > Good idea, and that's a step forward. Any references > or is it still an idea? > > Cheers, > > Chaosheng > > ----- Original Message ----- > From: "Isobel Clark" <[EMAIL PROTECTED]> > To: "AI Geostats mailing list" <[EMAIL PROTECTED]> > Sent: Monday, December 06, 2004 1:07 PM > Subject: Re: [ai-geostats] F and T-test for samples > drawn from the same p > > > > Dear all > > > > I am having difficulty understanding why none of > you > > want to try a spatial approach to statistics. > Everyone > > is trying to make the 'independent' statistical > tests > > work on spatial data. Try turning this around and > look > > at the spatial aspect first. > > > > (1) Testing variances: the sill on the > semi-variogram > > (total height of model) is theoretically a good > > estimate for the sample variance when > auto-correlation > > or spatial dependence is present. Do your F test > on > > that. Yes, you still have degrees of freedom > problems, > > but with thousands of samples the 'infinity > column' > > should be sufficient. > > > > (2) Testing means: the classic t-test in the > presence > > of 'equal variances' requires the 'standard error' > of > > each mean. For independent samples, this is > s/sqrt(n). > > For spatially dependent samples, this is the > kriging > > standard error for the global mean. Your only > problem > > then is getting a global standard error. > > > > Isobel > > http://geoecosse.bizland.com/whatsnew.htm > > > > > > > ---------------------------------------------------------------------------- > ---- > > > > * By using the ai-geostats mailing list you agree > to follow its rules > > ( see > http://www.ai-geostats.org/help_ai-geostats.htm ) > > > > * To unsubscribe to ai-geostats, send the > following in the subject or in > the body (plain text format) of an email message to > [EMAIL PROTECTED] > > > > Signoff ai-geostats > > > > > > * By using the ai-geostats mailing list you agree to > follow its rules > ( see > http://www.ai-geostats.org/help_ai-geostats.htm ) > > * To unsubscribe to ai-geostats, send the following > in the subject or in the body (plain text format) of > an email message to [EMAIL PROTECTED] > > Signoff ai-geostats
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