If Y = A + A*X, where A is a constant, X is an independent variable, and you know that X has uncertainty Delta X, then uncertainty in Y is: Delta Y = A * Delta X. Anatoly ________________________________ From: ifeffit-bounces@millenia.cars.aps.anl.gov [ifeffit-bounces@millenia.cars.aps.anl.gov] on behalf of Rana, Jatinkumar Kantilal [jatinkumar.rana@helmholtz-berlin.de] Sent: Friday, November 16, 2012 1:33 PM To: ifeffit@millenia.cars.aps.anl.gov Subject: [Ifeffit] Determining errors in R_fit Dear Ifeffit users, I have a very simple doubt about reporting the uncertainties in R_fit. In the fit, I have assumed that a bond length changes by a constant fraction, *alpha* such that Delta R = R_effective * alpha and, R_fit = R_effective +/- Delta R I can get uncertainties in the fitted value of *alpha* from artemis. But the question is how to work out the uncertainties in the R_fit. Will it be same as that of *alpha* ?? Thanks in advance !!! With best regards, Jatin ________________________________ Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Mitglied der Hermann von Helmholtz-Gemeinschaft Deutscher Forschungszentren e.V. Aufsichtsrat: Vorsitzender Prof. Dr. Dr. h.c. mult. Joachim Treusch, stv. Vorsitzende Dr. Beatrix Vierkorn-Rudolph Geschäftsführung: Prof. Dr. Anke Rita Kaysser-Pyzalla, Thomas Frederking Sitz Berlin, AG Charlottenburg, 89 HRB 5583 Postadresse: Hahn-Meitner-Platz 1 D-14109 Berlin http://www.helmholtz-berlin.de