# centiles: Plots the centile curves for a GAMLSS object In gamlss: Generalised Additive Models for Location Scale and Shape

## Description

This function `centiles()` plots centiles curves for distributions belonging to the GAMLSS family of distributions. The function also tabulates the sample percentages below each centile curve (for comparison with the model percentages given by the argument `cent`.) The function `centiles.fan()` plots a fan-chart of the centile curves. A restriction of the functions is that it applies to models with one explanatory variable only.

## Usage

 ``` 1 2 3 4 5 6 7 8 9 10 11 12``` ```centiles(obj, xvar, cent = c(0.4, 2, 10, 25, 50, 75, 90, 98, 99.6), legend = TRUE, ylab = "y", xlab = "x", main = NULL, main.gsub = "@", xleg = min(xvar), yleg = max(obj\$y), xlim = range(xvar), ylim = range(obj\$y), save = FALSE, plot = TRUE, points = TRUE, pch = 15, cex = 0.5, col = gray(0.7), col.centiles = 1:length(cent) + 2, lty.centiles = 1, lwd.centiles = 1, ...) centiles.fan(obj, xvar, cent = c(0.4, 2, 10, 25, 50, 75, 90, 98, 99.6), ylab = "y", xlab = "x", main = NULL, main.gsub = "@", xleg = min(xvar), yleg = max(obj\$y), xlim = range(xvar), ylim = range(obj\$y), points = FALSE, median = TRUE, pch = 15, cex = 0.5, col = gray(0.7), colors = c("cm", "gray", "rainbow", "heat", "terrain", "topo"), ...) ```

## Arguments

 `obj` a fitted gamlss object from fitting a gamlss distribution `xvar` the unique explanatory variable `cent` a vector with elements the % centile values for which the centile curves have to be evaluated `legend` whether a legend is required in the plot or not, the default is `legent=TRUE` `ylab` the y-variable label `xlab` the x-variable label `main` the main title here as character. If NULL the default title "centile curves using NO" (or the relevant distributions name) is shown `main.gsub` if the `main.gsub` (with default "@") appears in the `main` title then it is substituted with the default title. `xleg` position of the legend in the x-axis `yleg` position of the legend in the y-axis `xlim` the limits of the x-axis `ylim` the limits of the y-axis `save` whether to save the sample percentages or not with default equal to `FALSE`. In this case the sample percentages are printed but are not saved `plot` whether to plot the centiles. This option is useful for `centile.split` `pch` the character to be used as the default in plotting points see `par` `cex` size of character see `par` `col` plotting colour see `par` `col.centiles` Plotting colours for the centile curves `lty.centiles` line type for the centile curves `lwd.centiles` The line width for the centile curves `colors` the different colour schemes to be used for the fan-chart. The following are available `c("cm","gray", "rainbow", "heat", "terrain", "topo")`, `points` whether the data points should be plotted, default is `TRUE` for `centiles()` and `FALSE` for `centiles.fan()` `median` whether the median should be plotted (only in `centiles.fan()`) `...` for extra arguments

## Details

Centiles are calculated using the fitted values in `obj` and `xvar` must correspond exactly to the predictor in `obj` to plot correctly.

`col.centiles`, `lty.centiles` and `lwd.centiles` may be vector arguments and are recycled to the length `cent` if necessary.

## Value

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

## Warning

This function is appropriate only when one continuous explanatory variable is fitted in the model

## Author(s)

Mikis Stasinopoulos d.stasinopoulos@londonmet.ac.uk, Bob Rigby r.rigby@londonmet.ac.uk with contribution from Steve Ellison

## 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.

`gamlss`, `centiles.split` , `centiles.com`

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15``` ```data(abdom) h<-gamlss(y~pb(x), sigma.formula=~pb(x), family=BCT, data=abdom) # default plot centiles(h,xvar=abdom\$x) # control of colours and lines centiles(h, xvar=abdom\$x, col.cent=c(2,3,4,5,1,5,4,3,2,1), lwd.cent=c(1,1,1,1,2,1,1,1,1)) #Control line types centiles(h, xvar=abdom\$x, col.cent=1, cent=c(.5,2.5,50,97.5,99.5), lty.centiles=c(3,2,1,2,3),lwd.cent=c(1,1,2,1,1)) # control of the main title centiles(h, xvar=abdom\$x, main="Abdominal data \n @") # the fan-chart centiles.fan(h,xvar=abdom\$x, colors="rainbow") rm(h) ```

### Example output     ```Loading required package: splines
**********   GAMLSS Version 5.0-2  **********
For more on GAMLSS look at http://www.gamlss.org/
Type gamlssNews() to see new features/changes/bug fixes.

GAMLSS-RS iteration 1: Global Deviance = 4771.925
GAMLSS-RS iteration 2: Global Deviance = 4771.039
GAMLSS-RS iteration 3: Global Deviance = 4770.999
GAMLSS-RS iteration 4: Global Deviance = 4770.994
GAMLSS-RS iteration 5: Global Deviance = 4770.993
% of cases below  0.4 centile is  0.3278689
% of cases below  2 centile is  2.459016
% of cases below  10 centile is  8.688525
% of cases below  25 centile is  26.22951
% of cases below  50 centile is  50.16393
% of cases below  75 centile is  73.77049
% of cases below  90 centile is  90
% of cases below  98 centile is  98.03279
% of cases below  99.6 centile is  99.67213
% of cases below  0.4 centile is  0.3278689
% of cases below  2 centile is  2.459016
% of cases below  10 centile is  8.688525
% of cases below  25 centile is  26.22951
% of cases below  50 centile is  50.16393
% of cases below  75 centile is  73.77049
% of cases below  90 centile is  90
% of cases below  98 centile is  98.03279
% of cases below  99.6 centile is  99.67213
% of cases below  0.5 centile is  0.6557377
% of cases below  2.5 centile is  2.459016
% of cases below  50 centile is  50.16393
% of cases below  97.5 centile is  97.70492
% of cases below  99.5 centile is  99.5082
% of cases below  0.4 centile is  0.3278689
% of cases below  2 centile is  2.459016
% of cases below  10 centile is  8.688525
% of cases below  25 centile is  26.22951
% of cases below  50 centile is  50.16393
% of cases below  75 centile is  73.77049
% of cases below  90 centile is  90
% of cases below  98 centile is  98.03279
% of cases below  99.6 centile is  99.67213
```

gamlss documentation built on March 31, 2021, 5:10 p.m.