# densityplot

##### Kernel Probability Density Plots

Draw Kernel Density plots

- Keywords
- hplot

##### Usage

`densityplot(formula, data, n = 50, plot.points = TRUE, ref = FALSE, ...)`

##### Arguments

- formula
- A formula of the form
`~ x | g1 * g2 * ...`

indicating that density plots of`x`

should be produced conditional on the levels of the variables`g1,g2,...`

.`x`

must be numeric, and each of - data
- data frame in which variables are to be evaluated.
- n
- number of points at which density is to be evaluated
- plot.points
- logical specifying whether the
`x`

values should be plotted. - ref
- logical specifying whether a reference x-axis should be drawn.
- ...
- arguments to be passed down to the panel function, in
turn to be passed to
`density`

(if the default panel function is used).

##### Details

See the documentation for `trellis.args`

for description of other
valid arguments. The density estimate is actually calculated using the
function `density`

, and all arguments accepted by it can be
passed (as `...`

) in the call to `densityplot`

to control
the output. See documentation of `density`

for details. (Note: The
default value of the argument `n`

of `density`

is changed to
50.)

##### Value

- An object of class ``trellis'', plotted by default by
`print.trellis`

.

##### synopsis

densityplot(formula, data = parent.frame(), aspect = "fill", layout = NULL, panel = panel.densityplot, prepanel = NULL, scales = list(), strip = TRUE, groups = NULL, xlab, xlim, ylab, ylim, bw = NULL, adjust = NULL, kernel = NULL, window = NULL, width = NULL, give.Rkern = FALSE, n = 50, from = NULL, to = NULL, cut = NULL, na.rm = NULL, ..., subscripts = !is.null(groups), subset = TRUE)

##### See Also

`trellis.args`

, `density`

,
`panel.densityplot`

,
`panel.mathdensity`

,`Lattice`

##### Examples

```
data(singer)
densityplot( ~ height | voice.part, data = singer, layout = c(2, 4),
xlab = "Height (inches)", bw = 5)
## Using a predefined panel function to fit a normal distribution
densityplot( ~ height | voice.part, data = singer, layout = c(2, 4),
xlab = "Height (inches)",
ylab = "Kernel Density/ Normal Fit",
main = list("Estimated Density", cex = 2, col = "DarkOliveGreen"),
panel = function(x, ...) {
panel.xyplot(x = jitter(x),
y = rep(0, length(x)))
panel.densityplot(x, ...)
panel.mathdensity(dmath = dnorm,
args = list(mean=mean(x),sd=sd(x)))
} )
```

*Documentation reproduced from package lattice, version 0.3-1, License: GPL version 2 or later*