Because they test different hypothesis. ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek / Research Institute for Nature and Forest team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance Kliniekstraat 25 1070 Anderlecht Belgium
To call in the statistician after the experiment is done may be no more than asking him to perform a post-mortem examination: he may be able to say what the experiment died of. ~ Sir Ronald Aylmer Fisher The plural of anecdote is not data. ~ Roger Brinner The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data. ~ John Tukey 2015-05-26 21:46 GMT+02:00 li li <hannah....@gmail.com>: > Thanks so much for replying. > Yes LimerTest package could be used to get pvalues when using lmer > function. But still the summary and anova function give different > pvalues. > Hanna > > 2015-05-26 15:19 GMT-04:00, byron vinueza <byronvin...@hotmail.com>: > > You can use the lmerTest package . > > > > > > > > > > > > Enviado desde mi iPhone > > > >> El 26/5/2015, a las 13:18, li li <hannah....@gmail.com> escribió: > >> > >> Hi all, > >> I am using the lme function to run a random coefficient model. Please > >> see > >> output (mod1) as below. > >> I need to obtain the pvalue for the fixed effect. As you can see, > >> the pvalues given using the summary function is different from the > >> resutls given in anova function. > >> Why should they be different and which one is the correct one to use? > >> Thanks! > >> Hanna > >> > >> > >>> summary(mod1) > >> Linear mixed-effects model fit by REML > >> Data: minus20C1 > >> AIC BIC logLik > >> -82.60042 -70.15763 49.30021 > >> > >> Random effects: > >> Formula: ~1 + months | lot > >> Structure: General positive-definite, Log-Cholesky parametrization > >> StdDev Corr > >> (Intercept) 8.907584e-03 (Intr) > >> months 6.039781e-05 -0.096 > >> Residual 4.471243e-02 > >> > >> Fixed effects: ti ~ type * months > >> Value Std.Error DF t-value p-value > >> (Intercept) 0.25831245 0.016891587 31 15.292373 0.0000 > >> type 0.13502089 0.026676101 4 5.061493 0.0072 > >> months 0.00804790 0.001218941 31 6.602368 0.0000 > >> type:months -0.00693679 0.002981859 31 -2.326329 0.0267 > >> Correlation: > >> (Intr) typ months > >> type -0.633 > >> months -0.785 0.497 > >> type:months 0.321 -0.762 -0.409 > >> > >> Standardized Within-Group Residuals: > >> Min Q1 Med Q3 Max > >> -2.162856e+00 -1.962972e-01 -2.771184e-05 3.749035e-01 2.088392e+00 > >> > >> Number of Observations: 39 > >> Number of Groups: 6 > >>> anova(mod1) > >> numDF denDF F-value p-value > >> (Intercept) 1 31 2084.0265 <.0001 > >> type 1 4 10.8957 0.0299 > >> months 1 31 38.3462 <.0001 > >> type:months 1 31 5.4118 0.0267 > >> > >> _______________________________________________ > >> r-sig-mixed-mod...@r-project.org mailing list > >> https://stat.ethz.ch/mailman/listinfo/r-sig-mixed-models > > > > _______________________________________________ > r-sig-mixed-mod...@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-sig-mixed-models > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.