Dear List,

I am struggling with the following problem: I am trying to model water

surface in the southern Florida with data coming from 200 different water

stations. The area is divided by canals and levees so there is no real

hydrological connection for the entire area. If I split the area by canals /

levees there are 9 distinct smaller areas inside which I can assume

hydrological connection, but some areas have too little data to do kriging �

for example. So I am trying to use deterministic methods to see if I am

getting anything meaningful. I cannot put aside 10 or 20% of the data and do

a validation because I already have a too small set of data as it is for the

big area I am working on.

Later on I may have some data to try to do a comparison between known data

points and predictions, but for now I don�t have access to this second set

of data and I have to generate some discussion if not some results for the

end of the year report (as usual). So � supposing I have two interpolation

models and the single �statistics� I have access to is cross-validation with

mean and root mean square errors. Comparing the cross-validation statistics

of model A and model B I have: m(A) < m(B) and RMS(A) > RMS(B). Which model

I should expect to be better? If you want to work with numbers, let�s

suppose that m(A) = 0.01, RMS(A) = 1.05, and m(B) = 0.04 and RMS(B) = 0.7.

Any suggestions will be greatly appreciated.

Monica

_________________________________________________________________

On the road to retirement? Check out MSN Life Events for advice on how to

get there!

http://lifeevents.msn.com/category.aspx?cid=Retirement