stats.S {qcc}

Functions to plot Shewhart S chart

Description

These functions are used to compute statistics required by the S chart.

Usage

stats.S(data, sizes)
sd.S(data, sizes, std.dev = c("UWAVE-SD", "MVLUE-SD", "RMSDF"))
limits.S(center, std.dev, sizes, conf)

Arguments

data

the observed data values

center

sample/group center statistic.

sizes

samples sizes. Optional

std.dev

within group standard deviation. Optional for sd.S function, required for limits.S. See sd.xbar.

conf

a numeric value used to compute control limits, specifying the number of standard deviations (if conf > 1) or the confidence level (if 0 < conf < 1).

Value

The function stats.S returns a list with components statistics and center.

The function sd.S returns std.dev the standard deviation of the statistic charted.

The function limits.S returns a matrix with lower and upper control limits.

Author(s)

Luca Scrucca

References

Montgomery, D.C. (2005) Introduction to Statistical Quality Control, 5th ed. New York: John Wiley & Sons.
Wetherill, G.B. and Brown, D.W. (1991) Statistical Process Control. New York: Chapman & Hall.

See Also

qcc