plotdeplot.lmscreg {VGAM} | R Documentation

## Density Plot for LMS Quantile Regression

### Description

Plots a probability density function associated with a LMS quantile regression.

### Usage

    plotdeplot.lmscreg(answer, y.arg, add.arg = FALSE,
        xlab = "", ylab = "density",
        xlim = NULL, ylim = NULL,
        llty.arg = par()$lty, col.arg = par()$col,
        llwd.arg = par()$lwd, ...)

### Arguments

`answer` | Output from functions of the form `deplot.???` where `???` is the name of the VGAM LMS family function, e.g., `lms.yjn`. See below for details.
`y.arg` | Numerical vector. The values of the response variable at which to evaluate the density. This should be a grid that is fine enough to ensure the plotted curves are smooth.
`add.arg` | Logical. Add the density to an existing plot?
`xlab, ylab` | Caption for the x- and y-axes. See `par`.
`xlim, ylim` | Limits of the x- and y-axes. See `par`.
`llty.arg` | Line type. See the `lty` argument of `par`.
`col.arg` | Line color. See the `col` argument of `par`.
`llwd.arg` | Line width. See the `lwd` argument of `par`.
`...` | Arguments passed into the `plot` function when setting up the entire plot. Useful arguments here include `main` and `las`.

### Details

The above graphical parameters offer some flexibility when plotting the quantiles.

### Value

The list `answer`, which has components

`newdata` | The argument `newdata` above from the argument list of `deplot.lmscreg`, or a one-row data frame constructed out of the `x0` argument.
`y` | The argument `y.arg` above.
`density` | Vector of the density function values evaluated at `y.arg`.

### Note

While the graphical arguments of this function are useful to the user, this function should not be called directly.

### Author(s)

Thomas W. Yee

### References

Yee, T. W. (2004) Quantile regression via vector generalized additive models. Statistics in Medicine, 23, 2295–2315.

Documentation accompanying the VGAM package at http://www.stat.auckland.ac.nz/~yee contains further information and examples.

### See Also

`deplot.lmscreg`.

### Examples

    fit = vgam(BMI ~ s(age, df=c(4,2)), fam=lms.bcn(zero=1), data=bminz)
    ## Not run:
    y = seq(15, 43, by=0.25)
    deplot(fit, x0=20, y=y, xlab="BMI", col="green", llwd=2,
           main="BMI distribution at ages 20 (green), 40 (blue), 60 (red)")
    deplot(fit, x0=40, y=y, add=TRUE, col="blue", llwd=2)
    deplot(fit, x0=60, y=y, add=TRUE, col="red", llwd=2) -> a

    names(a@post$deplot)
    a@post$deplot$newdata
    head(a@post$deplot$y)
    head(a@post$deplot$density)
    ## End(Not run)

[Package VGAM version 0.7-9 Index]