get_Lb_ddf {pbkrtest} | R Documentation |
Get adjusted denomintor degress freedom for testing Lb=0 in a linear mixed model where L is a restriction matrix.
get_Lb_ddf(object, L) Lb_ddf(L, V0, Vadj)
object |
A linear mixed model object. |
L |
A vector with the same length as |
V0, Vadj |
Unadjusted and adjusted covariance matrix for the fixed effects
parameters. Undjusted covariance matrix is obtained with
|
Adjusted degrees of freedom (adjusment made by a Kenward-Roger approximation).
Soren Hojsgaard, sorenh@math.aau.dk
Ulrich Halekoh, Søren Højsgaard (2014)., A Kenward-Roger Approximation and Parametric Bootstrap Methods for Tests in Linear Mixed Models - The R Package pbkrtest., Journal of Statistical Software, 58(10), 1-30., http://www.jstatsoft.org/v59/i09/
KRmodcomp
,
vcovAdj
,
model2restrictionMatrix
,
restrictionMatrix2model
(fmLarge <- lmer(Reaction ~ Days + (Days|Subject), sleepstudy)) ## removing Days (fmSmall <- lmer(Reaction ~ 1 + (Days|Subject), sleepstudy)) anova(fmLarge,fmSmall) KRmodcomp(fmLarge,fmSmall) ## 17 denominator df's get_Lb_ddf(fmLarge, c(0,1)) ## 17 denominator df's # Notice: The restriction matrix L corresponding to the test above # can be found with L<-model2restrictionMatrix(fmLarge, fmSmall) L