Compute ANOVA from the car
package
and Anova
function.
Arguments
- mod
lm, aov, glm, multinom, polr mlm, coxph, coxme, lme, mer, merMod, svyglm, svycoxph, rlm, or other suitable model object.
- error
for a linear model, an lm model object from which the error sum of squares and degrees of freedom are to be calculated. For F-tests for a generalized linear model, a glm object from which the dispersion is to be estimated. If not specified, mod is used.
- type
type of test, "II", "III", 2, or 3. Roman numerals are equivalent to the corresponding Arabic numerals.
- white.adjust
if not FALSE, the default, tests use a heteroscedasticity-corrected coefficient covariance matrix; the various values of the argument specify different corrections. See the documentation for hccm for details. If white.adjust=TRUE then the "hc3" correction is selected.
Value
An object of class "anova", or "Anova.mlm", which usually is printed. For objects of class "Anova.mlm", there is also a summary method, which provides much more detail than the print method about the MANOVA, including traditional mixed-model univariate F-tests with Greenhouse-Geisser and Huynh-Feldt corrections.
Details
Calculates type-II or type-III analysis-of-variance tables for model objects produced by lm, glm, multinom (in the nnet package), polr (in the MASS package), coxph (in the survival package), coxme (in the coxme pckage), svyglm and svycoxph (in the survey package), rlm (in the MASS package), lmer in the lme4 package, lme in the nlme package, and (by the default method) for most models with a linear predictor and asymptotically normal coefficients (see details below). For linear models, F-tests are calculated; for generalized linear models, likelihood-ratio chisquare, Wald chisquare, or F-tests are calculated; for multinomial logit and proportional-odds logit models, likelihood-ratio tests are calculated. Various test statistics are provided for multivariate linear models produced by lm or manova. Partial-likelihood-ratio tests or Wald tests are provided for Cox models. Wald chi-square tests are provided for fixed effects in linear and generalized linear mixed-effects models. Wald chi-square or F tests are provided in the default case.
Author
John Fox jfox@mcmaster.ca; the code for the Mauchly test and Greenhouse-Geisser and Huynh-Feldt corrections for non-spericity in repeated-measures ANOVA are adapted from the functions stats:::stats:::mauchly.test.SSD and stats:::sphericity by R Core; summary.Anova.mlm and print.summary.Anova.mlm incorporates code contributed by Gabriel Baud-Bovy.
Examples
# \donttest{
m <- lm(mpg ~ cyl + disp, data = mtcars)
car_Anova(m)
#> Anova Table (Type II tests)
#>
#> Response: mpg
#> Sum Sq Df F value Pr(>F)
#> cyl 46.418 1 4.9720 0.03366 *
#> disp 37.594 1 4.0268 0.05419 .
#> Residuals 270.740 29
#> ---
#> Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
# }