Dear Sibylle, I suspect your residuals will never become normal, because your data are counts. Luckily, normality is not a requirement for variogram calculation nor for kriging interpolation.
However, before calculating variograms it may be a good idea to correct for non-stationarity in the variances, and work with Pearson residuals. See: Gotway, C.A., Stroup, W.W. (1997) A Generalized Linear Model Approach to Spatial Data Analysis and Prediction. Journal of Agricultural, Biological and Environmental Statistics 2(2), pp. 157--178. Diggle, P.J., Liang, K-Y., Zeger, S.L. (1994) Analysis of Longitudinal Data. Oxford University Press, Oxford. or the more advanced approach of: Diggle, P.J., J.A. Tawn, R.A. Moyeed (1998), Model-based geostatistics. Applied Statistics 47(3), pp 299-350. -- Edzer -- * 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
