Abstract
One of the frequent questions by users of the mixed model function lmer of the lme4 package has been: How can I get p values for the F and t tests for objects returned by lmer? The lmerTest package extends the 'lmerMod' class of the lme4 package, by overloading the anova and summary functions by providing p values for tests for fixed effects. We have implemented the Satterthwaite's method for approximating degrees of freedom for the t and F tests. We have also implemented the construction of Type I - III ANOVA tables. Furthermore, one may also obtain the summary as well as the anova table using the Kenward-Roger approximation for denominator degrees of freedom (based on the KRmodcomp function from the pbkrtest package). Some other convenient mixed model analysis tools such as a step method, that performs backward elimination of nonsignificant effects - both random and fixed, calculation of population means and multiple comparison tests together with plot facilities are provided by the package as well.
Originalsprog | Engelsk |
---|---|
Tidsskrift | Journal of Statistical Software |
Vol/bind | 82 |
Udgave nummer | 13 |
Antal sider | 26 |
ISSN | 1548-7660 |
DOI | |
Status | Udgivet - 2017 |
Udgivet eksternt | Ja |
Emneord
- denominator degree of freedom
- Satterthwaite’s approximation
- ANOVA
- R
- linear mixed effects models
- lme4.