How can I from the summary function, decide which glm (fit1, fit2 or fit3) fits to data best? I don't know what to look after, so I would please explain the important output.
> fit1 <- glm(Y~X, family=gaussian(link="identity")) > fit2 <- glm(Y~X, family=gaussian(link="log")) > fit3 <- glm(Y~X, family=Gamma(link="log")) > summary(fit1) Call: glm(formula = Y ~ X, family = gaussian(link = "identity")) Deviance Residuals: Min 1Q Median 3Q Max -3.6619 -1.9693 -0.4119 2.0787 3.9664 Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) -0.4285 1.6213 -0.264 0.798258 X 4.3952 0.7089 6.200 0.000259 *** --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 (Dispersion parameter for gaussian family taken to be 6.784605) Null deviance: 315.081 on 9 degrees of freedom Residual deviance: 54.277 on 8 degrees of freedom AIC: 51.294 Number of Fisher Scoring iterations: 2 > summary(fit2) Call: glm(formula = Y ~ X, family = gaussian(link = "log")) Deviance Residuals: Min 1Q Median 3Q Max -1.5489 -0.2960 0.4776 0.6353 1.2773 Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 0.50537 0.16562 3.051 0.0158 * X 0.66352 0.05083 13.055 1.13e-06 *** --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 (Dispersion parameter for gaussian family taken to be 1.083989) Null deviance: 315.0810 on 9 degrees of freedom Residual deviance: 8.6718 on 8 degrees of freedom AIC: 32.954 Number of Fisher Scoring iterations: 6 > summary(fit3) Call: glm(formula = Y ~ X, family = Gamma(link = "log")) Deviance Residuals: Min 1Q Median 3Q Max -0.35269 -0.09272 0.02550 0.13625 0.18018 Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 0.85959 0.11244 7.645 6.04e-05 *** X 0.53134 0.04916 10.808 4.74e-06 *** --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 (Dispersion parameter for Gamma family taken to be 0.03262828) Null deviance: 4.31315 on 9 degrees of freedom Residual deviance: 0.28385 on 8 degrees of freedom AIC: 36.65 Number of Fisher Scoring iterations: 5 -- View this message in context: http://www.nabble.com/How-to-read-the-summary-tp23276848p23276848.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list 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.