Calculate the midpoints and limits for a centipede plot

Calculates midpoints and limits for a list or data frame for use with centipede.plot.

Usage

get.segs(x,mct="mean",lower.limit="std.error",upper.limit=lower.limit)

Arguments

x: a list or data frame.
mct: The name of the function to calculate midpoints.
lower.limit,upper.limit: The names of the function(s) to calculate lower and upper limits.

Details

get.segs calls the functions whose names are passed to calculate midpoints and limits for each list element or data frame column. The user can define special functions for the central and dispersion measures if desired.

Value

A matrix with four rows and as many columns as were in the object

x. The first row contains the midpoint values, the second and third the lower and upper limit values respectively and the fourth row the number of valid observations in the columns.

Author

Jim Lemon