vcd (version 1.4-3)

pairs.table: Pairs Plot for Contingency Tables

Description

Produces a matrix of strucplot displays.

Usage

"pairs"(x, upper_panel = pairs_mosaic, upper_panel_args = list(), lower_panel = pairs_mosaic, lower_panel_args = list(), diag_panel = pairs_diagonal_mosaic, diag_panel_args = list(), main = NULL, sub = NULL, main_gp = gpar(fontsize = 20), sub_gp = gpar(fontsize = 15), space = 0.3, newpage = TRUE, pop = TRUE, return_grob = FALSE, margins = unit(1, "lines"), ...)

Arguments

x

a contingency table in array form, with optional category labels specified in the dimnames(x) attribute.

upper_panel

function for the upper triangle of the matrix, or corresponding generating function. If NULL, no panel is drawn.

upper_panel_args

list of arguments for the generating function, if specified.

lower_panel

function for the lower triangle of the matrix, or corresponding generating function. If NULL, no panel is drawn.

lower_panel_args

list of arguments for the panel-generating function, if specified.

diag_panel

function for the diagonal of the matrix, or corresponding generating function. If NULL, no panel is drawn.

diag_panel_args

list of arguments for the generating function, if specified.

main

either a logical, or a character string used for plotting the main title. If main is a logical and TRUE, the name of the object supplied as x is used.

sub

a character string used for plotting the subtitle. If sub is a logical and TRUE and main is unspecified, the name of the object supplied as x is used.

main_gp, sub_gp

object of class "gpar" containing the graphical parameters used for the main (sub) title, if specified.

space

double specifying the distance between the cells.

newpage

logical controlling whether a new grid page should be created.

pop

logical indicating whether all viewports should be popped after the plot has been drawn.

return_grob

logical. Should a snapshot of the display be returned as a grid grob?

margins

either an object of class "unit" of length 4, or a numeric vector of length 4. The elements are recycled as needed. The four components specify the top, right, bottom, and left margin of the plot, respectively. When a numeric vector is supplied, the numbers are interpreted as "lines" units. In addition, the unit or numeric vector may have named arguments (top, right, bottom, and left), in which case the non-named arguments specify the default values (recycled as needed), overloaded by the named arguments.

...

For convenience, list of arguments for the panel-generating functions of upper and lower panels, if specified.

Details

This is a pairs method for objects inheriting from class "table" or "structable". It plots a matrix of pairwise mosaic plots. Four independence types are distinguished: "pairwise", "total", "conditional" and "joint". The pairwise mosaic matrix shows bivariate marginal relations, collapsed over all other variables. The total independence mosaic matrix shows mosaic plots for mutual independence, i.e., for marginal and conditional independence among all pairs of variables. The conditional independence mosaic matrix shows mosaic plots for conditional independence for each pair of variables, given all other variables. The joint independence mosaic matrix shows mosaic plots for joint independence of all pairs of variables from the others.

This method uses panel functions called for each cell of the matrix which can be different for upper matrix, lower matrix, and diagonal cells. Correspondingly, for each panel parameter foo (= upper, lower, or diag), pairs.table takes two arguments: foo\_panel and foo\_panel\_args, which can be used to specify the parameters as follows:

1. Passing a suitable panel function to foo\_panel which subsequently is called for each cell with the corresponding coordinates.
2. Passing a corresponding generating function (of class "panel_generator") to foo\_panel, along with parameters passed to foo\_panel\_args, that generates such a function.

Hence, the second approach is equivalent to the first if foo\_panel(foo\_panel\_args) is passed to foo\_panel.

References

Cohen, A. (1980), On the graphical display of the significant components in a two-way contingency table. Communications in Statistics---Theory and Methods, A9, 1025--1041.

Friendly, M. (1992), Graphical methods for categorical data. SAS User Group International Conference Proceedings, 17, 190--200. http://datavis.ca/papers/sugi/sugi17.pdf

Meyer, D., Zeileis, A., and Hornik, K. (2006), The strucplot framework: Visualizing multi-way contingency tables with vcd. Journal of Statistical Software, 17(3), 1-48. URL http://www.jstatsoft.org/v17/i03/ and available as vignette("strucplot").

See Also

pairs_mosaic, pairs_assoc, pairs_sieve, pairs_diagonal_text, pairs_diagonal_mosaic, pairs_text, pairs_barplot, assoc, sieve, mosaic

Examples

data("UCBAdmissions")
data("PreSex")
data(HairEyeColor)
hec = structable(Eye ~ Sex + Hair, data = HairEyeColor)

pairs(PreSex)
pairs(UCBAdmissions)
pairs(UCBAdmissions, upper_panel_args = list(shade = TRUE))
pairs(UCBAdmissions, lower_panel = pairs_mosaic(type = "conditional"))
pairs(UCBAdmissions, diag_panel = pairs_text)
pairs(UCBAdmissions, upper_panel = pairs_assoc, shade = TRUE)
pairs(hec, highlighting = 2, diag_panel_args = list(fill = grey.colors))
pairs(hec, highlighting = 2, diag_panel = pairs_diagonal_mosaic,
           diag_panel_args = list(fill = grey.colors, alternate_labels =TRUE))