anova
for objects
inheriting from class
gam
.
See
anova
for the general behavior of this function
and for the interpretation of the aguments.
anova.gam(object, ..., test)
When called with a single
gam
object, a special anova table
for
gam
models is returned.
This gives a breakdown of the degrees of freedom for all the
terms in the model, separating the projection part and nonparametric
part of each.
For example, a term specified by
s
is broken down into a
single degree of freedom for its linear component,
and the remainder for the nonparametric component.
In addition, a type of score test is performed for each
of the nonparametric terms.
The nonparametric component is set to zero, and the
linear part is updated, holding the other nonparametric terms fixed.
This is done efficiently and simultaneously for all terms.
Chambers, J.M., and Hastie, T.J. (1991). Statistical Models in S, pp. 210-213, 273.
# create a sample gam object gam.object <- gam(Kyphosis ~ lo(Number) + lo(Start, degree = 2), data = kyphosis) anova(gam.object) # produces the following output: DF for Terms and F-values for Nonparametric Effects Df Npar Df Npar F Pr(F) (Intercept) 1 lo(Number) 1 2.8 0.870022 0.4540488 lo(Start, degree = 2) 2 4.0 1.838448 0.1309525