Likelihood ratio test of cumulative link models
Comparison of cumulative link models in likelihood ratio tests. The models may differ by terms in location, scale and nominal formulae, in link, threshold function and random effect structure.
## S3 method for class 'clm2'
anova(object, ..., test = c("Chisq", "none"))
## S3 method for class 'clmm2'
anova(object, ..., test = c("Chisq", "none"))The method returns an object of class Anova (for printing) and
data.frame with the following elements
Model |
character description of the cumulative link models being compared. Location, scale and nominal formulae are separated by "|"s in this order. |
Resid.df |
the residual degrees of freedom |
-2logLik |
twice the negative log likelihood (proportional to the deviance) |
Test |
indication of which models are being compared. |
DF |
the difference in the degrees of freedom in the models being compared, i.e. the degrees of freedom for the chi-squared test. |
LR stat. |
the likelihood ratio statistic. |
Pr(Chi) |
the p-value from the likelihood ratio test. Absent if
|
Rune Haubo B Christensen
clm2, addterm,
dropterm and
anova.default
options(contrasts = c("contr.treatment", "contr.poly"))
m1 <- clm2(SURENESS ~ PROD, scale = ~PROD, data = soup,
link = "logistic")
## anova
anova(m1, update(m1, scale = ~.-PROD))
mN1 <- clm2(SURENESS ~ 1, nominal = ~PROD, data = soup,
link = "logistic")
anova(m1, mN1)
anova(m1, update(m1, scale = ~.-PROD), mN1)
## Fit model from polr example:
if(require(MASS)) {
fm1 <- clm2(Sat ~ Infl + Type + Cont, weights = Freq, data = housing)
anova(fm1, update(fm1, scale =~ Cont))
}Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.