search for: epsilon_ij

...dom effect intercept term. The reason why I want to do this is test for the significance of the random effect intercept term. anova( , ) does not work for an lm model and lme model together. 2) Is there some nice way of handling linear models which are of the form response_ij = a_i + b_i x_ij + \epsilon_ij where a_i and b_i are fixed effects, x_ij is given (continuous) data, \epsilon_ij ~ N(0, \sigma^2), and the i's range over some group? This is basically a group of regression models, but I want them handled as one unit for the purposes of estimation of \sigma^2 etc. I know that lmList() does...

Dear R users, I am trying to fit the following ANCOVA model in R2.4.0 Y_ij=mu+alpha_i+beta*(X_ij-X..)+epsilon_ij Particularly I am interested in obtaining estimates for mu, and the effects alpha_i I have this data (from the book Applied Linear Statistical Models by Neter et al (1996), page 1020) y<-c(38,43,24,39,38,32,36,38,31,45,27,21,33,34,28) x<-c(21,34,23,26,26,29,22,29,30,28,18,16,19,25,29)...

...ntra-subject trajectories of Y very close to linear. I'd like to check whether slope (and maybe also offset) of this line are (in part) predicted by X.baseline. Thus, I think the multilevel model specification should be as follows (i = subject, j=measurement): y_ij = \beta_i + b_i * TIME_ij + \epsilon_ij, with b_i = \zeta_i0 + \zeta_i1 * X.Baseline Is this correct? Now, I am completely unsure how to "translate" this into the syntax needed by lme. Is there any standard procedure on how to get from e.g. the Laird&Ware'82 matrix model notation to the lme input? And, in my case, is t...

Dear people, A somewhat clueless question follows: I just discovered that the lme function in contrib package nlme for R, while similar to the lme function in Splus, does not use the cluster function option. This difference does not appear to be documented in the V&R `R Complements' file. I have data which is divided into 6 groups The lme model is of the form (simplified from the actual