loess
object, that is, a fitted local
regression model returned by the
loess
function, and produces an
Analysis of Variance Table.
anova.loess(object, ... , test = "F")
"F"
,
"none"
, and
"Cp"
.
"anova"
.
"F"
, F tests are carried
out; object k is tested against object k-1 with the scale estimate
from the object with the largest value of
enp
.
For
"Cp"
,
Mallows' statistic is computed with the scale estimate
from the object with the largest value of
enp
.
For
"none"
, no test is carried out.
This function is a method for the generic function for class loess. It can be invoked by calling for an object x of the appropriate class, or directly by calling regardless of the class of the object.
Chambers, J.M., and Hastie, T.J. (1991). Statistical Models in S, 210-213, 330.
attach(ethanol) # create sample objects gas.m <- loess(formula = NOx ~ E, span = 1, data = gas) gas.m.null <- loess(formula = NOx ~ E, span = 2/3, data = gas) anova(gas.m.null, gas.m) # produces the following output: Model 1: loess(formula = NOx ~ E, data = gas, span = 1) Model 2: loess(formula = NOx ~ E, data = gas, span = 2/3) Analysis of Variance Table ENP RSS Test F Value Pr(F) 1 3.5 4.8489 1 vs 2 10.14 0.0008601 2 5.5 1.7769