topic Lackfit test for weighted regression in SAS Programming https://communities.sas.com/t5/SAS-Programming/Lackfit-test-for-weighted-regression/m-p/100836#M258115 <HTML><HEAD></HEAD><BODY><P>Does anybody know the formula for the Lack of Fit test in case of WEIGHTED regression (linear and nonlinear)? proc reg has for example the lackfit option (also for weighted LS). Thanks! </P></BODY></HTML> Wed, 02 Oct 2013 11:13:33 GMT Stela 2013-10-02T11:13:33Z Lackfit test for weighted regression https://communities.sas.com/t5/SAS-Programming/Lackfit-test-for-weighted-regression/m-p/100836#M258115 <HTML><HEAD></HEAD><BODY><P>Does anybody know the formula for the Lack of Fit test in case of WEIGHTED regression (linear and nonlinear)? proc reg has for example the lackfit option (also for weighted LS). Thanks! </P></BODY></HTML> Wed, 02 Oct 2013 11:13:33 GMT https://communities.sas.com/t5/SAS-Programming/Lackfit-test-for-weighted-regression/m-p/100836#M258115 Stela 2013-10-02T11:13:33Z Re: Lackfit test for weighted regression https://communities.sas.com/t5/SAS-Programming/Lackfit-test-for-weighted-regression/m-p/100837#M258116 <HTML><HEAD></HEAD><BODY><P>Educated guess: Since the lack of fit test is a F test, it will involve the ratio of sums of weighted squares instead of the ratio of sums of squares, with the same degrees of freedom.</P><P>hth</P><P></P><P>PG </P></BODY></HTML> Thu, 03 Oct 2013 02:48:50 GMT https://communities.sas.com/t5/SAS-Programming/Lackfit-test-for-weighted-regression/m-p/100837#M258116 PGStats 2013-10-03T02:48:50Z