# fixef.lmekin: Extraction functions for Lmekin In coxme: Mixed Effects Cox Models

## 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

 1 2 3 4 5 6 7 8 9 10 ## 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 + e, let s^2 be the variance of the error term e. Let A = sP 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.

## Examples

 1 2 3 data(ergoStool, package="nlme") # use a data set from nlme efit <- lmekin(effort ~ Type + (1|Subject), ergoStool) ranef(efit)

### Example output

Attaching package: 'bdsmatrix'

The following object is masked from 'package:base':

backsolve

\$Subject
8             5             4             9             6
-1.708721e+00 -1.495131e+00 -8.543605e-01 -2.135901e-01  3.335141e-16
3             7             1             2
4.271802e-01  4.271802e-01  1.708721e+00  1.708721e+00

coxme documentation built on May 13, 2018, 5:03 p.m.