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

Description Usage Arguments Value Author(s) References See Also

View source: R/qcc.R

Description

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

Usage

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stats.np(data, sizes)
sd.np(data, sizes, ...)
limits.np(center, std.dev, sizes, conf)

Arguments

data

the observed data values

center

sample/group center statistic.

sizes

samples sizes.

std.dev

within group standard deviation.

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).

...

further arguments are ignored.

Value

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

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

The function limits.np 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


qcc documentation built on May 2, 2019, 9:15 a.m.