# freqpolygon: Frequency Polygons In ProjectMOSAIC/mosaic: Project MOSAIC Statistics and Mathematics Teaching Utilities

## Description

Frequency polygons are an alternative to histograms that make it simpler to overlay multiple distributions.

## Usage

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16``` ```freqpolygon(x, ..., panel = "panel.freqpolygon", prepanel = "prepanel.default.freqpolygon") prepanel.default.freqpolygon(x, darg = list(), plot.points = FALSE, ref = FALSE, groups = NULL, subscripts = TRUE, jitter.amount = 0.01 * diff(current.panel.limits()\$ylim), center = NULL, nint = NULL, breaks = NULL, width = darg\$width, type = "density", ...) panel.freqpolygon(x, darg = list(), plot.points = FALSE, ref = FALSE, groups = NULL, weights = NULL, jitter.amount = 0.01 * diff(current.panel.limits()\$ylim), type = "density", breaks = NULL, nint = NULL, center = NULL, width = darg\$width, gcol = trellis.par.get("reference.line")\$col, glwd = trellis.par.get("reference.line")\$lwd, h, v, ..., identifier = "freqpoly") ```

## Arguments

 `x` a formula or a numeric vector `...` additional arguments passed on to `histogram()` and `panel`. `panel` a panel function `prepanel` a prepanel function `darg` a list of arguments for the function computing the frequency polygon. This exists primarily for compatibility with `densityplot` and is unlikely to be needed by the end user. `plot.points` one of `TRUE`, `FALSE`, `"jitter"`, or `"rug"` indicating how points are to be displayed `ref` a logical indicating whether a horizontal reference line should be added (roughly equivalent to `h=0`) `groups, weights, jitter.amount, identifier` as in `densityplot()` or `histogram()` `subscripts` as in other lattice prepanel functions `center` center of one of the bins `nint` an approximate number of bins for the frequency polygon `breaks` a vector of breaks for the frequency polygon bins `width` width of the bins `type` one of `'density'`, `'percent'`, or `'count'` `gcol` color of guidelines `glwd` width of guidelines `h, v` a vector of values for additional horizontal and vertical lines

a trellis object

## Note

This function make use of `histogram` to determine overall layout. Often this works reasonably well but sometimes it does not. In particular, when `groups` is used to overlay multiple frequency polygons, there is often too little head room. In the latter cases, it may be necessary to use `ylim` to determine an appropriate viewing rectangle for the plot.

## Examples

 ```1 2 3 4 5 6 7``` ```freqpolygon(~age | substance, data=HELPrct, v=35) freqpolygon(~age, data=HELPrct, labels=TRUE, type='count') freqpolygon(~age | substance, data=HELPrct, groups=sex) freqpolygon(~age | substance, data=HELPrct, groups=sex, ylim=c(0,0.11)) ## comparison of histogram and frequency polygon histogram(~eruptions, faithful, type='density', width=.5) ladd( panel.freqpolygon(faithful\$eruptions, width=.5 )) ```

ProjectMOSAIC/mosaic documentation built on Aug. 19, 2018, 9:14 a.m.