pdf.plot: Plots Probability Distribution Functions for GAMLSS Family

In gamlss: Generalized Additive Models for Location Scale and Shape

Plots Probability Distribution Functions for GAMLSS Family

Description

A function to plot probability distribution functions (pdf) belonging to the gamlss family of distributions. This function allows either plotting of the fitted distributions for up to eight observations or plotting specified distributions belonging in the gamlss family

Usage

pdf.plot(obj = NULL, obs = c(1), family = NO(), mu = NULL, 
         sigma = NULL, nu = NULL, tau = NULL, from = 0, 
         to = 10, min = NULL, max = NULL, no.points = 201, 
         no.title = FALSE, col = gray(0.4), y.axis.lim = 1.1, 
         frame.plot = TRUE, ...)         

Arguments

obj	An gamlss object e.g. obj=model1 where model1 is a fitted gamlss object
obs	A number or vector of up to length eight indicating the case numbers of the observations for which fitted distributions are to be displayed, e.g. obs=c(23,58) will display the fitted distribution for the 23th and 58th observations
family	This must be a gamlss family i.e. family=NO
mu	The value(s) of the location parameter mu for which the distribution has to be evaluated e.g mu=c(3,7)
sigma	The value(s) the scale parameter sigma for which the distribution has to be evaluated e.g sigma=c(3,7)
nu	The value(s) the parameter nu for which the distribution has to be evaluated e.g. nu=3
tau	The value(s) the parameter tau for which the distribution has be evaluated e.g. tau=5
from	Minimum value of the random variable y (identical to min)
to	Maximum value of the random variable y(identical to max)
min	Minimum value of the random variable y e.g. min=0
max	Maximum value of y e.g. max=10
no.points	the number fo point in which the function will be evaluated
no.title	Whether you need title in the plot, default is no.title=FALSE
col	the colot of the lines
y.axis.lim	the limits for the y-axis
frame.plot	whether to frame the individual plots
...	for extra arguments, Note that a useful argument can be col.axis, col.lab, cex.axis, cex.lab etc.

Details

This function can be used to plot distributions of the GAMLSS family. If the first argument obj is specified and it is a GAMLSS fitted object, then the fitted distribution of this model at specified observation values (given by the second argument obs) is plotted for a specified y-variable range (arguments min, max, and step).

If the first argument is not given then the family argument has to be specified and the pdf is plotted at specified values of the parameters mu, sigma, nu, tau. Again the range of the y-variable has to be given.

Value

plot(s) of the required pdf(s) are returned

Warning

The range of some distributions depends on the fitted parameters

Note

The range of the y values given by min, max and step are very important in the plot

Author(s)

Mikis Stasinopoulos and Calliope Akantziliotou

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.

Rigby, R. A., Stasinopoulos, D. M., Heller, G. Z., and De Bastiani, F. (2019) Distributions for modeling location, scale, and shape: Using GAMLSS in R, Chapman and Hall/CRC. An older version can be found in https://www.gamlss.com/.

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, https://www.jstatsoft.org/v23/i07/.

Stasinopoulos D. M., Rigby R.A., Heller G., Voudouris V., and De Bastiani F., (2017) Flexible Regression and Smoothing: Using GAMLSS in R, Chapman and Hall/CRC.

(see also https://www.gamlss.com/).

See Also

gamlss

Examples

pdf.plot(family=BCT, min=1, max=20, mu=10, sigma=0.15, nu=-1, tau=c(4,10,20,40) )
## Not run: 
# now using an gamlss object
data(abdom)
h<-gamlss(y~pb(x), sigma.formula=~pb(x), family=BCT, data=abdom) # fits 
pdf.plot(obj=h , obs=c(23,67), min=50, max=150)

## End(Not run)

gamlss documentation built on May 29, 2024, 6:08 a.m.