| rqres.plot {gamlss} | R Documentation |
This function plots worm plots, van Buuren and Fredriks M. (2001), or QQ-plots of the normalized randomized quantile residuals (Dunn and Smyth, 1996) for a model using a discrete GAMLSS family distribution.
rqres.plot(obj = NULL, howmany = 6, plot = c("all", "average"),
type = c("wp", "QQ"), ...)
obj |
a fitted GAMLSS model object from a "discrete" type of family |
howmany |
The number of QQ-plots required up to ten i.e. |
plot |
whether to plot all plots all the residual realisations |
type |
whether to plot worm plots |
... |
for extra arguments tp be passed to |
For discrete family distributions, the gamlss() function saves on exit one realization of randomized quantile residuals which
can be plotted using the generic function plot which calls the plot.gamlss. Looking at only one realization can be misleading, so the
current function creates QQ-plots for several
realizations. The function allows up to 10 QQ-plots to be plotted. Occasionally one wishes to create a lot of realizations
and then take a median of them (separately for each ordered value) to create a single median realization. The option all in combinations
with the option howmany creates a
QQ-plot of the medians of the normalized randomized quantile residuals. These 'median' randomized quantile residuals can be saved using the option
(save=TRUE).
If save it is TRUE then the vector of the median residuals is saved.
Mikis Stasinopoulos d.stasinopoulos@londonmet.ac.uk
Dunn, P. K. and Smyth, G. K. (1996) Randomised quantile residuals, J. Comput. Graph. Statist., 5, 236–244
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.
van Buuren and Fredriks M. (2001) Worm plot: simple diagnostic device for modelling growth reference curves. Statistics in Medicine, 20, 1259–1277
data(aids) # fitting a model from a discrete distribution h<-gamlss(y~pb(x)+qrt, family=NBI, data=aids) # plot(h) # plot qq- plots from 6 realization of the randomized quantile residuals rqres.plot(h) # a qq-plot from the medians from 40 realizations rqres.plot(h,howmany=40,plot="average") #