lspline: Create Linear Splines

In uwIntroStats: Descriptive Statistics, Inference, Regression, and Plotting in an Introductory Statistics Course

Description

Creates linear splines, mostly for use in regression.

Usage

lspline(x, knots, lbl=NULL, 
        parameterization="absolute", version=FALSE)
lsplineD(x, knots, lbl=NULL, version=FALSE)

Arguments

x	variable used to create the linear splines.
knots	vector of knots to create the splines.
lbl	a label for the splines.
parameterization	defaults to"absolute", and provides splines based on the absolute slope between knots. If "change", provides splines based on the change from knot to knot. If lsplineD is called, "change" is entered by default.
version	if TRUE, returns the version of the function and nothing else.

Value

A matrix containing the linear splines.

Author(s)

Scott S. Emerson, M.D., Ph.D., Andrew J. Spieker, Brian D. Williamson

Examples

# Reading in a dataset
mri <- read.table("http://www.emersonstatistics.com/datasets/mri.txt", header=TRUE)
attach(mri)
# Create a spline based on absolute
lspline(ldl, c(70, 100, 130, 160))

# Create a spline based on change
lsplineD(ldl, c(70, 100, 130, 160))

uwIntroStats documentation built on May 2, 2019, 4:34 a.m.