raschmix-plot-method: Profile Plot of Item Parameters

Description

The plot method for raschmix-class objects gives a base plot of the item parameter profiles in each class. A lattice plot of the item parameters is returned by xyplot. A rootogram or histogram of the posterior probabilities is plotted via histogram.

Usage

# S4 method for raschmix,missing
plot(x, y, component = NULL, difficulty = TRUE,
                   center = TRUE, index = TRUE, names = TRUE,
                   abbreviate = FALSE, ref = TRUE, col =  "black",
                   refcol = "lightgray", linecol = NULL, lty = 2, cex = 1,
                   pch = 19, type = NULL, ylim = NULL, xlab = "Items",
                   ylab = NULL, legend = TRUE, pos = "topright",
                   srt = 45, adj = c(1.1, 1.1), ...)
# S3 method for raschmix
histogram(x, data, root = TRUE, ...)
# S3 method for raschmix
xyplot(x, data, component = NULL, item = NULL,
  difficulty = TRUE, plot.type = c("multiple", "single"),
  auto.key = NULL, type = "b", lty = NULL, xlab = "Item", ylab = NULL,
  panel = NULL, scales = NULL, ...)

Arguments

x: An object of class "raschmix".
y: Not used.
component: A vector indicating which components should be plotted.
difficulty: Logical. Should item difficulty parameters be used?
center: Logical. Should the item parameters be centered around 0?
index: Logical. Should the index be used for labelling the items?
names: Either logical or an optional vector of names used for labeling of the items.
abbreviate: Logical. Should the labels of the items be abbreviated?
ref: Logical. Should a reference line be drawn?
col: Point color. If col is a vector, it is interpreted as the color of the components respectively. Individual coloring within components is possible if col is given as a matrix with each column representing one component.
refcol: Color of the reference line.
linecol: Line color. Defaults to the point color.
lty, cex, pch, type, ylim, xlab, ylab: Further standard graphical parameters.
legend: Logical. Should a legend be included?
pos: Position of the legend.
srt, adj: Passed on to text() if names = TRUE.
...: Further graphical parameters.
data: Ignored.
root: Logical. Should a rootogram be drawn?
item: A vector indicating which items should be plotted.
plot.type: Should the item profiles be drawn in multiple panels or a single panel?
auto.key, panel, scales: Further graphical parameters for lattice.

Details

For a graphical representation of the item parameter in each class use plot (for a base graph) or xyplot (for a lattice plot).

For a graphical representation of the quality of the mixture use histogram. For details see plot-methods.

References

Frick, H., Strobl, C., Leisch, F., and Zeileis, A. (2012). Flexible Rasch Mixture Models with Package psychomix. Journal of Statistical Software, 48(7), 1--25. tools:::Rd_expr_doi("10.18637/jss.v048.i07").

Leisch, F. (2004). FlexMix: A General Framework for Finite Mixture Models and Latent Class Regression in R. Journal of Statistical Software, 11(8), 1--18. tools:::Rd_expr_doi("10.18637/jss.v011.i08").

Leisch, F. (2004). Exploring the Structure of Mixture Model Components. In Jaromir Antoch, editor, Compstat 2004 -- Proceedings in Computational Statistics, pages 1405--1412. Physika Verlag, Heidelberg, Germany. ISBN 3-7908-1554-3.