Important: The stats package has been deprecated. Use the superseding package Statistics instead.

The function scatterplot with the format parameter format=excised of the subpackage stats[statplots] removes the fraction of least dense data and plots a scatterplot of the remaining data.

This type of plot is often used when there is a large number of data points involved.  The idea is that it is not necessary to have the detail of each individual point in a plot.  Closely grouped points are supposedly more representative, so all other points are excised.

When p is a positive number between zero and one, p times the number of points are excised from the plot.  In other words only the $\left(1-p\right)\mathrm{numpoints}$ most densely clustered points are plotted in the scatter plot.

When p is a negative number between zero and -1, $p\mathrm{numpoints}$ of the most densely clustered points are excised from the plot.  In this case $\left(1-p\right)\mathrm{numpoints}$ of the least densely clustered points are plotted in the scatter plot.

The default, when p is not specified is zero.  This plot is identical to a scatter plot with no format parameter.

Relative density of points is calculated approximately by finding the distances between all points using the distance metric $\exp \left(-\|\mathrm{p1}-\mathrm{p2}\|\right)$.

Class data is converted to classmarks before generating the plot.  Weighted data is accounted for.  Missing data is ignored.

The command with(stats[statplots]) allows the use of the abbreviated form of this command.

$\mathrm{with}\left(\mathrm{stats}\right)\:$

$\mathrm{with}\left(\mathrm{stats}\left[\mathrm{statplots}\right]\right)\:$

$\mathrm{data1}≔\left[\mathrm{random}\left[\mathrm{normald}\right]\left(30\right)\,\mathrm{random}\left[\mathrm{normald}\left[3,1\right]\right]\left(20\right)\right]\:$

$\mathrm{data2}≔\left[\mathrm{random}\left[\mathrm{normald}\right]\left(30\right)\,\mathrm{random}\left[\mathrm{normald}\left[3,1\right]\right]\left(20\right)\right]\:$

$\mathrm{scatterplot}\left(\mathrm{data1}\,\mathrm{data2}\,\mathrm{format}=\mathrm{excised}\left[0.5\right]\right)$

$\mathrm{data3}≔\left[12.00\,\mathrm{Weight}\left(10\,3\right)\,8..9.5\,9.67\,11.11\,10.34\right]\:$

$\mathrm{scatterplot}\left(\mathrm{data3}\,\mathrm{format}=\mathrm{excised}\right)$