IQCC (version 0.7)

cchart.R: R control chart

Description

This function builds a R control chart.

Usage

cchart.R(x, n, type = "norm", y = NULL)

Arguments

x

The data to be plotted.

n

The sample size.

type

The type of R chart to be plotted. The options are "norm" (traditional Shewhart R chart) and "tukey" (exact R chart). If not specified, a Shewhart R chart will be plotted.

y

The data used in phase I to estimate the standard deviation.

Value

Return a R control chart.

Details

The Shewhart R chart was designed for phase I (at this moment). The limits of the exact R chart are the alpha/2 and 1-alpha/2 quantiles of the R distribution that are calculated as estimated process sd times the quantiles of the relative range (W=R/sigma) distribution.

Examples

# NOT RUN {
data(pistonrings)
attach(pistonrings)
cchart.R(pistonrings[1:25,], 5)
cchart.R(pistonrings[26:40, ], 5, type = "tukey", pistonrings[1:25, ])

# }