stats.R: Statistics used in computing and drawing a Shewhart R chart

In luca-scr/qcc: Quality Control Charts

Statistics used in computing and drawing a Shewhart R chart

Description

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

Usage

stats.R(data, sizes)
sd.R(data, sizes, std.dev = c("UWAVE-R", "MVLUE-R"), ...)
limits.R(center, std.dev, sizes, nsigmas = NULL, conf = NULL)

Arguments

data	the observed data values
center	sample/group center statistic.
sizes	samples sizes. Optional
std.dev	within group standard deviation. Optional for sd.R function, required for limits.R. See sd.xbar.
nsigmas	a numeric value specifying the number of sigmas to use for computing control limits. It is ignored when the conf argument is provided.
conf	a numeric value in (0,1) specifying the confidence level to use for computing control limits.
...	catches further ignored arguments.

Value

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

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

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

Author(s)

Luca Scrucca

References

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

Wetherill, G.B. and Brown, D.W. (1991) Statistical Process Control. New York: Chapman & Hall.

See Also

qcc

luca-scr/qcc documentation built on Feb. 25, 2023, 3:33 p.m.