gamlss (version 5.1-4)

calibration: Calibrating centile curves

Description

This function can used when the fitted model centiles do not coincide with the sample centiles.

Usage

calibration(object, xvar, cent = 100 * pnorm((-4:4) * 2/3),
            legend = FALSE, fan = FALSE, ...)

Arguments

object

a gamlss fitted object

xvar

The explanatory variable

cent

a vector with elements the % centile values for which the centile curves have to be evaluated

legend

whether legend is required

fan

whether to use the fan version of centiles

…

other argument pass on to centiles() function

Value

A centile plot is produced and the sample centiles below each centile curve are printed (or saved)

Details

The function finds the sample quantiles of the residuals of the fitted model (the z-scores) and use them as sample quantile in the argument cent of the centiles() function. This procedure is appropriate if the fitted model centiles do not coincide with the sample centiles and when this failure is the same in all values of the explanatory variable xvar.

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. (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.

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 http://www.gamlss.org/).

See Also

centiles, centiles.fan

Examples

# NOT RUN {
data(abdom)
m1<-gamlss(y~pb(x), sigma.fo=~pb(x), family=LO, data=abdom)
calibration(m1, xvar=abdom$x, fan=TRUE)
# }