Computes a likelihood ratio test between a reduced model (modr) and a full model (modr). Both models must be previously fitted by maximum likelihood using an R function such as nlme() and such, that are part of the generalized lineal models.
lrt.glm(modr, modf)This function returns an object having the following elements: "loglik.Modr" maximized log-likelihood of modr; "loglik.Modf" maximized log-likelihood of modf; "dif.loglik" difference in log-likelihood between both models, and "dif.df" difference in degrees of freedong of both models, and "p-value" is the p-value for the LRT.
is the object containing a previously fitted reduced model, using a glm-type of function, having less parameters than modf.
is the object containing a previously fitted full model, using a glm-type of function, having more parameters than modr.
Christian Salas-Eljatib.
Double-check the order of the reduced and full model, before of using the model
Pinheiro JC, and Bates DM. 2000. Mixed-effects models in S and Splus. Springer-Verlag, New York, NY. 528 p.