fixef.lmekin {coxme} R Documentation

## Extraction functions for Lmekin

### Description

Extract the fixed effects, random effects, variance of the fixed effects, or variance of the random effects from a linear mixed effects model fit with lmekin.

### Usage

## S3 method for class 'lmekin'
fixef(object, ...)
## S3 method for class 'lmekin'
ranef(object, ...)
## S3 method for class 'lmekin'
vcov(object, ...)
## S3 method for class 'lmekin'
VarCorr(x, ...)
## S3 method for class 'lmekin'
logLik(object, ...)


### Arguments

 object an object inheriting from class lmekin representing the result of a mixed effects model. x an object inheriting from class lmekin representing the result of a mixed effects model. ... some methods for this generic require additional arguments. None are used in this method.

### Details

For the random effects model y = X\beta + Zb + \epsilon, let \sigma^2 be the variance of the error term \epsilon. Let A= \sigma^2 P be the variance of the random effects b. There is a computational advantage to solving the problem in terms of P instead of A, and that is what is stored in the returned lmekin object. The VarCorr function returns elements of P; the print and summary functions report values of A. Pinhiero and Bates call P the precision factor.

### Value

the fixed effects are a vector and vcov returns their variance/covariance matrix. The random effects are a list with one element for each random effect. The ranef component contains the coefficients and VarCorr the estimated variance/covariance matrix. The logLik method returns the loglikelihood along with its degrees of freedom.

Terry Therneau

### References

J Pinheiro and D Bates, Mixed-effects models in S and S-Plus. Springer, 2000.

lmekin, random.effects, fixed.effects, link{vcov}, VarCorr
data(ergoStool, package="nlme")  # use a data set from nlme