nos.qqplot {NostalgiR}

nos.qqplot text-based generic quantile-quantile plots

Description

Produces a text-based quantile-quantile plot between two equal size samples, with the option of plotting a line of theoretical quantile equality.

Usage

nos.qqplot(x, y, xlab = NULL, ylab = NULL, line = T, ratio = 0.25,
  width = round(options()$width * 0.8), height = round(ratio * width),
  pch = c("o", "~"))

Arguments

x

A numeric vector containing the values to be plotted along the x-axis. NA and NaN are allowed, but are removed for the plot. Infinities will cause an error.

y

A numeric vector containing the values to be plotted along the y-axis. NA and NaN are allowed, but are removed for the plot. Infinities will cause an error.

xlab

Label of the x-axis of the plot.

ylab

Label of the y-axis of the plot.

line

If TRUE, the line of theoretical quantile equality is plotted. If FALSE, then the line of theoretical quantile equality is not plotted.

ratio

Coefficient that controls the aspect ratio of the plot.

width

Width of the plot in points.

height

Height of the plot in points.

pch

A two dimensional vector of single-character symbols. The first symbol is for data point, and the second symbol is for the line of theoretical quantile equality.

Note

Due to rounding to a relatively crude grid results can only be approximate. The equally spaced axis ticks, for example, may be non-equally spaced in the plot. Further, due to the crude grid also there might be several points per character. The function uses the same plotting symbol no matter how many points coincide on one character position.

Author(s)

Hien D. Nguyen

See Also

qqplot, qqline, ppoints, and txtplot.

Examples

## Produce a quantile-quantile plot between two samples of 10 random standard normal points,
## without the line of theoretical quantile equality.
x <- rnorm(10)
y <- rnorm(10)
nos.qqplot(x,y,line=FALSE)

## Produce a quantile-quantile plot of 100 random chi-squared(3) points against the
## true theoretical distribution, with the line of theoretical quantile equality.
y <- rchisq(100,3)
x <- qchisq(ppoints(100),3)
nos.qqplot(x,y,xlab='Theoretical Qs',ylab='Sample Qs')