R: Highest Density Region Boxplots

hdr.boxplot {hdrcde} | R Documentation

## Highest Density Region Boxplots

### Description

Calculates and plots a univariate highest density regions boxplot.

### Usage

    hdr.boxplot(
      x,
      prob = c(99, 50),
      h = hdrbw(BoxCox(x, lambda), mean(prob)),
      lambda = 1,
      boxlabels = "",
      col = gray((9:1)/10),
      main = "",
      xlab = "",
      ylab = "",
      pch = 1,
      border = 1,
      outline = TRUE,
      space = 0.25,
      ...
    )

### Arguments

`x` | Numeric vector containing data or a list containing several vectors.
`prob` | Probability coverage required for HDRs `density`.
`h` | Optional bandwidth for calculation of density.
`lambda` | Box-Cox transformation parameter where `0 <= lambda <= 1`.
`boxlabels` | Label for each box plotted.
`col` | Colours for regions of each box.
`main` | Overall title for the plot.
`xlab` | Label for x-axis.
`ylab` | Label for y-axis.
`pch` | Plotting character.
`border` | Width of border of box.
`outline` | If not <code>TRUE</code>, the outliers are not drawn.
`space` | The space between each box, between 0 and 0.5.
`...` | Other arguments passed to plot.

### Details

The density is estimated using kernel density estimation. A Box-Cox transformation is used if `lambda!=1`, as described in Wand, Marron and Ruppert (1991). This allows the density estimate to be non-zero only on the positive real line. The default kernel bandwidth `h` is selected using the algorithm of Samworth and Wand (2010).

Hyndman's (1996) density quantile algorithm is used for calculation.

### Value

nothing.

### Author(s)

Rob J Hyndman

### References

Hyndman, R.J. (1996) Computing and graphing highest density regions. American Statistician, 50, 120-126.

Samworth, R.J. and Wand, M.P. (2010). Asymptotics and optimal bandwidth selection for highest density region estimation. The Annals of Statistics, 38, 1767-1792.

Wand, M.P., Marron, J S., Ruppert, D. (1991) Transformations in density estimation. Journal of the American Statistical Association, 86, 343-353.

### See Also

`hdr.boxplot.2d`, `hdr`, `hdr.den`

### Examples

    # Old faithful eruption duration times
    hdr.boxplot(faithful$eruptions)

    # Simple bimodal example
    x <- c(rnorm(100,0,1), rnorm(100,5,1))
    par(mfrow=c(1,2))
    boxplot(x)
    hdr.boxplot(x)

    # Highly skewed example
    x <- exp(rnorm(100,0,1))
    par(mfrow=c(1,2))
    boxplot(x)
    hdr.boxplot(x,lambda=0)

[Package hdrcde version 3.4 Index]