Hi folks, Wondering if anyone might be able to help me on this one. I have just done some geochemistry with X-ray Diffraction and Rietveld Refinement in order to quantify the data. I have a observed spectra from my sample and a calculated spectra from the Rietveld Refinement (in the attached image, along with the background). I was wondering is there a package in R that I might be able to use that would essentially show me how well (or how poorly) fitted the Rietveld calculated spectra was with regard to my observed spectra? It's essentially a goodness of fit or R-squared value but I've been having some difficulty finding the right way to assess the model fit. I'd appreciate any information or tips anyone might have. Kind regards, Rory Flood. -- Rory Flood Postgraduate Research Student Room 02 044, Elmwood Building School of Geography, Archaeology and Palaeoecology Queen's University Belfast Belfast BT7 1NN Co. Antrim Northern Ireland Tel: +44 (0) 28 9097 3929 Email: rflood02 at qub.ac.uk __________________________________ <http://r.789695.n4.nabble.com/file/n4678470/Spectra.jpg> -- View this message in context: http://r.789695.n4.nabble.com/Goodness-of-fit-for-a-Rietveld-Refinement-tp4678470.html Sent from the R help mailing list archive at Nabble.com.