> I have performed a jacknife estimation of e variable > V1* in a 3D space, the reference file have the true > values of V1. Then I get the local error as > ERR=V1-V1*. The problem is that correlation > coefficient have large values for V1 and the other > variables (0.7-0.9) and by theory the error must to > be independent of the V1. Sorry, that's not true. The error is independent of V1* but never of V1, especially if you are using a linear estimator such as kriging.
> Why it happen, it is really dangerous in resource > estimation? This is known as conditional bias and, in short, YES! This effect has been documented for 50 years and has variously been known as the regression effect, the mine call factor, the volume/variance effect, conditional bias and many other things (not all of them polite!). Isobel Clark http://geoecosse.bizland.com/whatsnew.htm ________________________________________________________________________ Want to chat instantly with your online friends? Get the FREE Yahoo! Messenger http://uk.messenger.yahoo.com/ -- * To post a message to the list, send it to [EMAIL PROTECTED] * As a general service to the users, please remember to post a summary of any useful responses to your questions. * To unsubscribe, send an email to [EMAIL PROTECTED] with no subject and "unsubscribe ai-geostats" followed by "end" on the next line in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list * Support to the list is provided at http://www.ai-geostats.org
