clFun {qAnalyst}R Documentation

Internal function to compute upper or lower confidence limits for the specified control chart

Description

clFun calculates upper and lower confidence limits for control charts. Confidence limits are retuned as a vector.

Usage

clFun(x, sg, nSigma, cl, type = "xbar")

Arguments

x data vector
sg subgroup id for variable chart, subgroups dimension for variables chart, moving window interval in i / mr chart. A detailed description of sg field is in spc function help.
nSigma number of standard deviations from the center line
cl "u" or "l" respectively for upper or lower confidence limit
type type of control chart

Details

clFun allows to handle unequal sample size subgroups that makes confidence limits to vary. A warning is thrown if subgroup dimension is less than 2 when variables chart for groups are calculated.

Value

A vector of length equal to the number of points in the chart representing either lower o upper confidence limit.

Note

Internal function

Author(s)

Andrea Spano' and Giorgio Specicato

References

Montgomery, Statistical Quality Control

See Also

spc, plot.spc

Examples

#brakeCap dataset
data(brakeCap)
clFun(x=brakeCap$hardness, sg=brakeCap$subgroup, nSigma=2, cl="u", type="xbar")

[Package qAnalyst version 0.6.0 Index]