Multivariate Quality Control Charts

Plot an ellipse chart for a bivariate quality control data.

Usage

ellipseChart(object, chart.all = TRUE, show.id = FALSE, ngrid = 50,
             confidence.level, correct.multiple = TRUE, 
             title, xlim, ylim, xlab, ylab,
             restore.par = TRUE, ...)

Arguments

object: an object of class 'mqcc'.
chart.all: a logical value indicating whether both statistics for data and for newdata (if given) should be plotted.
show.id: a logical value indicating whether to plot point labels (TRUE) or symbols (FALSE) for group means.
ngrid: a value for the size of the grid over which the ellipse is evaluated.
confidence.level: a numeric value between 0 and 1 specifying the confidence level of the computed probability limits.
correct.multiple: a logical value indicating whether to correct or not for multiple comparisons.
title: a character string specifying the main title. Set title = FALSE or title = NA to remove the title.
xlim: a numeric vector specifying the limits for the x-axis.
ylim: a numeric vector specifying the limits for the y-axis.
xlab: a string giving the label for the x-axis.
ylab: a string giving the label for the y-axis.
restore.par: a logical value indicating whether the previous par settings must be restored. If you need to add points, lines, etc. to a control chart set this to FALSE.
...: additional arguments to be passed to the generic points function.

References

Mason, R.L. and Young, J.C. (2002) Multivariate Statistical Process Control with Industrial Applications, SIAM.

Montgomery, D.C. (2013) Introduction to Statistical Quality Control, 7th ed. New York: John Wiley & Sons.

Ryan, T. P. (2011), Statistical Methods for Quality Improvement, 3rd ed. New York: John Wiley & Sons, Inc.

Author

Luca Scrucca

Examples

# See examples in help(mqcc)