schweder function

Schweder and Spjotvoll plot

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

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 \mjseqn p-values
• xlab: Label for plot \mjseqn x-axis
• ylab: Label for plot \mjseqn 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 \mjseqn 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 Spjotvoll 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 \mjseqn 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.

Returns

A list containing - p: The values of \mjseqn 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

References

\insertRef becker94metap

\insertRef benjamini00metap

\insertRef schweder82metap

Author(s)

Michael Dewey

Examples

data(dat.metap)
   teachexpect <- dat.metap$teachexpect
   schweder(teachexpect)