# raschmix-plot-method

##### Profile Plot of Item Parameters

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`

.

- Keywords
- methods, raschmix-plot

##### 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.
http://www.jstatsoft.org/v48/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.
http://www.jstatsoft.org/v11/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.

*Documentation reproduced from package psychomix, version 1.1-8, License: GPL-2 | GPL-3*