R: Statistics used in computing and drawing the Hotelling T^2...

stats.T2.single {qcc}

R Documentation

Statistics used in computing and drawing the Hotelling T^2 chart for individual observations data

Description

These functions are used to compute statistics required by the T^2 chart for individual observations.

Usage

stats.T2.single(data, center = NULL, cov = NULL)

limits.T2.single(ngroups, size, nvars, conf)

Arguments

`data`	the observed data values
`center`	a vector of values to use for center of input variables.
`cov`	a matrix of values to use for the covariance matrix of input variables.
`ngroups`	number of groups
`size`	sample size
`nvars`	number of variables
`conf`	confidence level (0 < `conf` < 1)

Value

The function stats.T2.single returns a list with components:

`statistics`	a vector of values for the `T^2` statistic
`means`	a matrix of within group means for each variable (which is equal to `data` since sample are of sizes one)
`center`	sample/group center statistic
`S`	covariance matrix

The function limits.T2.single returns a list with components:

`control`	control limits
`prediction`	pred.limits

Author(s)

Luca Scrucca

References

Mason, R.L. and Young, J.C. (2002) Multivariate Statistical Process Control with Industrial Applications, SIAM.
Montgomery, D.C. (2005) Introduction to Statistical Quality Control, 5th ed. New York: John Wiley & Sons.
Ryan, T. P. (2000), Statistical Methods for Quality Improvement, 2nd ed. New York: John Wiley & Sons, Inc.