R: Plot regression terms for a specified parameter of a GAMLSS...

term.plot {gamlss}

R Documentation

Plot regression terms for a specified parameter of a GAMLSS object

Description

Plots regression terms against their predictors, optionally with standard errors and partial residuals added. It is almost identical to the R function termplot suitably changed to apply to GAMLSS objects.

Usage

term.plot(object, what = c("mu", "sigma", "nu", "tau"), data = NULL, 
          envir = environment(formula(object)), 
          partial.resid = FALSE, rug = FALSE, 
          terms = NULL, se = TRUE, xlabs = NULL, ylabs = NULL, 
          main = NULL, col.term = 2, lwd.term = 1.5, 
          col.se = "orange", lty.se = 2, lwd.se = 1, 
          col.res = "gray", cex = 1, pch = par("pch"), 
          col.smth = "darkred", lty.smth = 2, 
          span.smth = 2/3, 
          ask = interactive() && nb.fig < n.tms && .Device != "postscript", 
          use.factor.levels = TRUE, smooth = NULL,  ylim  = "common", ...)

Arguments

`object`	a GAMLSS object
`what`	the required parameter of the GAMLSS distribution
`data`	data frame in which variables in `object` can be found
`envir`	environment in which variables in `object` can be found
`partial.resid`	logical; should partial residuals be plotted?
`rug`	add rug plots (jitter 1-d histograms) to the axes?
`terms`	which terms to plot (default 'NULL' means all terms)
`se`	plot point-wise standard errors?
`xlabs`	vector of labels for the x axes
`ylabs`	vector of labels for the y axes
`main`	logical, or vector of main titles; if 'TRUE', the model's call is taken as main title, 'NULL' or 'FALSE' mean no titles.
`col.term, lwd.term`	colour and width for the "term curve", see 'lines'.
`col.se, lty.se, lwd.se`	colour, line type and line width for the "twice-standard-error curve" when 'se = TRUE'.
`col.res, cex, pch`	colour, plotting character expansion and type for partial residuals, when 'partial.resid = TRUE', see 'points'.
`lty.smth,col.smth, span.smth`	Passed to 'smooth'
`ask`	logical; if 'TRUE', the user is asked before each plot, see 'par(ask=.)'.
`use.factor.levels`	Should x-axis ticks use factor levels or numbers for factor terms?
`smooth`	'NULL' or a function with the same arguments as 'panel.smooth' to draw a smooth through the partial residuals for non-factor terms
`ylim`	an optional range for the y axis, or "common" when a range sufficient for all the plot will be computed, or "free" when limits are computed for each plot.
`...`	other graphical parameters

Details

The function uses the lpred function of GAMLSS. The 'data' argument should rarely be needed, but in some cases 'termplot' may be unable to reconstruct the original data frame. Using 'na.action=na.exclude' makes these problems less likely. Nothing sensible happens for interaction terms.

Value

a plot of fitted terms.

Author(s)

Mikis Stasinopoulos based on the existing termplot() function

References

Rigby, R. A. and Stasinopoulos D. M. (2005). Generalized additive models for location, scale and shape,(with discussion), Appl. Statist., 54, part 3, pp 507-554.

Stasinopoulos D. M., Rigby R.A. and Akantziliotou C. (2006) Instructions on how to use the GAMLSS package in R. Accompanying documentation in the current GAMLSS help files, (see also http://www.gamlss.org/).

Stasinopoulos D. M. Rigby R.A. (2007) Generalized additive models for location scale and shape (GAMLSS) in R. Journal of Statistical Software, Vol. 23, Issue 7, Dec 2007, http://www.jstatsoft.org/v23/i07.

Examples

data(aids)
a<-gamlss(y~pb(x)+qrt,data=aids,family=NBI)
term.plot(a, se=TRUE)
rm(a)

[Package gamlss version 4.3-0 Index]