polydeg: Degree of Polynomial Determination

In npsm: Nonparametric Statistical Methods

Degree of Polynomial Determination

Description

Tests for the degree of a polnomial. This test was suggested by Graybill (1976) and is discussed from a robust point-of-view in Section 4.7.1. of Kloke and McKean (2014)/4.6.1 of Kloke and McKean (2024).

Usage

polydeg(y, x, P, alpha = 0.05) 

Arguments

y	vector of responses
x	Predictor
P	Super degree of polynomial which provides a satisfactory fit
alpha	Level of the testing

Details

Returns the degree of the polynomial based on the algorithm.

Value

deg	The determined degree
coll	Matrix of step information
fitf	Fit of the polynomial based on the determoned degreer

References

Graybill, F.A. (1976), Theory and application of the linear model, North Scituate, Ma: Duxbury Press.

Kloke, J. and McKean, J.W. (2014), Nonparametric statistcal methods using R, Boca Raton, FL: Chapman-Hall. Kloke, J. and McKean, J.W. (2024), Nonparametric statistcal methods using R, Second Edition, Boca Raton, FL: Chapman-Hall.

Examples

 x <- 1:20
 xc <- x - mean(x)
 y<- .2*xc + xc^3 +rt(20,3)*90
 plot(y~x)
 polydeg(y,xc,6)

npsm documentation built on May 29, 2024, 3:07 a.m.