Dear r-helpers! Two closely related questions: 1) I would like to analyse the influence of a subdataset on the whole dataset (50 out of 350 datapoints) linear regression slope. I have read about influence.measures but this analyses only single datapoint. 2) I would like to compare the slope of the whole dataset with the slope of a subdataset consisting of the maximum values of 10 equal x-axis classes. any suggestions? Thanks Marcel ______________________________________________________________________________ Marcel Sandow Leibniz Institute of Marine Sciences - IFM-Geomar Experimental Ecology: Foodwebs D?sternbrooker Weg 20 24105 Kiel Germany Fon: +49-431-600-4404 Fax: +49-431-600-1515 Homepage: http://www.ifm-geomar.de E-mail: msandow at ifm-geomar.de