berryFunctions (version 1.4)

linReg: linear regression with plotting

Description

uses lm; plots data if add=FALSE, draws the regression line with abline and writes the formula with legend

Usage

linReg(x, y, digits=2, inset=0, xpd=par("xpd"), pos1="top", pos2=NULL,
add=FALSE, pch=20, col=2, lwd=3, xlab=deparse(substitute(x)),
ylab=deparse(substitute(y)), ...)

Arguments

x

Numeric. Vector with values of explanatory variable

y

Numeric. Vector with values of dependent variable

digits

Numeric vector of length $\ge 1$. Specifies number of digits a,b,r are rounded to in the formula "y=a*x+b \n R^2=r", respectively. If second and/or third value are not specified, they are set equal to the first. DEFAULT: 2

inset

Numeric vector of length $\le 2$. inset distance(s) from the margins as a fraction of the plot region when formula is placed by keyword. DEFAULT: 0

xpd

Logical, specifying wheter formula can be written only inside the plot region (when FALSE) or inside the figure region including mar (when TRUE) or in the entire device region including oma (when NA). DEFAULT: par("xpd")

pos1

xy.coords-acceptable position of the formula. DEFAULT: "top"

pos2

For numerical coordinates, this is the y-position. DEFAULT: NULL, as in legend

add

Logical. If TRUE, line and text are added to the existing graphic. DEFAULT: FALSE (plots datapoints first and then the line.)

pch

Point Character, see par. DEFAULT: 20

col

Color, see par. DEFAULT: 2

lwd

Numeric. Linewidth, see par. DEFAULT: 3

xlab

Character / Expression. X-axis label if add=FAlSE. DEFAULT: deparse(substitute(x))

ylab

Ditto for Y-Axis.

...

Further arguments passed to plot and abline.

Value

• None, used for plotting and drawing.

See Also

lm, legend, par, abline.

Examples

a <- 1:30
b <- a/2.345+rnorm(30,0,3)

linReg(a,b)
linReg(a,b, ylab="Hallo", pch=1, col=3, main="Regression by Berry")
linReg(a, b, pos1=15, pos2=0) # topleft corner of legend box (not drawn)

# For more flexibility with the datapoints, plot first, then use linReg with add=TRUE:
plot(a,b, xlim=c(-5,45))
linReg(a, b, pos1="bottomright", add=TRUE, inset=.1) # inset: distance from plot border
linReg(a, b, digits=c(7,4,3), add=TRUE, col=3, lty=2, lwd=4)
linReg(a, b, digits=3, pos1="topleft", inset=c(-0.1, 0.3), xpd=TRUE, add=TRUE)