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Last data update: 2014.03.03

R: Schweder and Spjotvoll plot

schweder

R Documentation

Schweder and Spjotvoll plot

Description

Produces the plot suggested by Schweder and Spjotvol to display a collection of p-values and also optionally draws the lowest slope line suggested by Benjamini and Hochberg

Usage

schweder(p, xlab = "Rank of p", ylab = "p", drawline = NULL,
   bh.lwd = 1, bh.lty = "solid", bh.col = "black",
   ls.control = list(frac = NULL),
   ls.lwd = 1, ls.lty = "dotted", ls.col = "black",
   ab.control = list(a = NULL, b = NULL),
   ab.lwd = 1, ab.lty = "dashed", ab.col = "black", ...)

Arguments

`p`	A vector of p-values
`xlab`	Label for plot x-axis
`ylab`	Label for plot y-axis
`drawline`	Which line, if any, to draw. See Details
`bh.lwd`	Width of the lowest slope line
`bh.lty`	Line type of the lowest slope line
`bh.col`	Colour of the lowest slope line
`ls.control`	A list containing a named element `frac`. See Details
`ls.lwd`	Width of the least squares line
`ls.lty`	Line type of the least squares line
`ls.col`	Colour of the least squares line
`ab.control`	A list containing two elements `a` and `b`. See Details
`ab.lwd`	Width of the specified line
`ab.lty`	Line type of the specified line
`ab.col`	Colour of the specified line
`...`	Further parameters to be passed through to plot

Details

After removing invalid p-values plots them. Any graphics parameters passed in ... affect this part of the plot only. Note that the axes are chosen according to the scheme of Banjamini and Hochberg, Schweder and Spjotvol used a different system.

By setting drawline appropriately up to three lines may be drawn.

If drawline includes the string "bh" the lowest slope line of Benjaimin and Hochberg is drawn. No further parameters are needed here but the characteristics of the line may be set: width, line type, and colour.

If drawline includes the string "ls" a least squares line is drawn passing through the point k+1, 1. The parameter frac specified what fraction of the values be used for this and may need experimentation to obtain a suitable line. The characteristics of the line may be set: width, line type, and colour.

If drawline includes the string "ab" a user specified line is drawn. The parameters a and b specify the intercept and slope. The characteristics of the line may be set: width, line type, and colour.

Value

A list containing

`p`	The values of p plotted
`bh.params`	A list containing at least items `a` and `b` the intercept and slope of the line drawn. This is only included if the lowest slope line was drawn
`ls.params`	A list containing at least items `a` and `b` the intercept and slope of the line drawn. This is only included if the least squares line was drawn
`ab.params`	A list containing at least items `a` and `b` the intercept and slope of the line drawn. This is only included if the user specified line was drawn

Author(s)

Michael Dewey

References

Benjamini, Y and Hochberg, Y. On the adaptive control of the false disovery rate in multiple testing with independent statistics. Journal of Educational and Behavioral Statistics, 25: 60–83, 2000.

Schweder, T and Spjotvoll, E. Plots of P–values to evaluate many tests simultaneously. Biometrika, 69:493–502, 1982.

Examples

   data(teachexpect)
   schweder(teachexpect)