qcc (version 2.6)

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

Description

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

Usage

stats.u(data, sizes)
sd.u(data, sizes, ...)
limits.u(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.u returns a list with components statistics and center.The function sd.u returns std.dev the standard deviation of the statistic charted.The function limits.u returns a matrix with lower and upper control limits.

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