Control Charts

Plot control charts

ss.cc(type, data, cdata, CTQ = names(data)[1], groups, climits, nsigmas = 3)

Arguments

type: Type of chart (see details)
data: data.frame with the process data.
cdata: Vector with the controlled process data to compute limits.
CTQ: Name of the column in the data.frame containing the CTQ.
groups: Name of the column in the data.frame containing the groups.
climits: Limits of the controlled process. It should contain three ordered values: lower limit, center line and upper limit.
nsigmas: Number of sigmas to compute the limits from the center line (default is 3)

Value

A plot with the control chart, and a list with the following elements:

LCL: Lower Control Limit
CL: Center Line
UCL: Upper Control Limit
phase: II when cdata or climits are provided. I otherwise.
out: Out of control points

Details

If control limits are provided, cdata is dismissed and a message is shown. If there are no control limits nor controlled data, the limits are computed using data.
Supported types of control charts:

mrMoving Range

Note

We have created this function since the qAnalyst package has been removed from CRAN, and it was used in the "Six Sigma with R" book to plot moving average control charts.

References

Cano, Emilio L., Moguerza, Javier M. and Redchuk, Andres. 2012. Six Sigma with R. Statistical Engineering for Process Improvement, Use R!, vol. 36. Springer, New York. https://link.springer.com/book/10.1007/978-1-4614-3652-2/.

Author

EL Cano

Examples

ss.cc("mr", ss.data.pb1, CTQ = "pb.humidity")

#> Phase I limits:
#>      LCL       CL      UCL 
#> 0.000000 1.569483 5.126767 
#> 
#> Out of control Moving Range:
#> None
testout <- ss.data.pb1
testout[31,] <- list(31,17)
ss.cc("mr", testout, CTQ = "pb.humidity")

#> Phase I limits:
#>      LCL       CL      UCL 
#> 0.000000 1.728600 5.646528 
#> 
#> Out of control Moving Range:
#> [1] 30