Given a variable sample, the function calculates the process capability and, assuming a normal distribution of the X chart, after the true control limits were found.
Usage
Cp_X(prev.results, LES, LEI, mu)
Value
Cp
The process capability index
Cpk
The process capability index in case is not centered
P.cp
The specification range percentage used by the control limits
X.sigma
The process standard deviation
Conclusion del proceso
A phrase to take conclusion about the process capability
Arguments
prev.results
Is a list of previous results obtained by the xrs_gr function in the first iteration, or the results obtained in further iterations by the X_it function.
LES
A numeric vector of length one, containing the upper specification limit.
LEI
A numeric vector of length one, containing the lower specification limit.
mu
A numeric vector of length one, containing the average specification, if not exists, function takes the Control Limit of previous results.
Author
Erick Marroquin
Details
The function stops for the lack of any arguments.
References
Montgomery, D.C. (2005) Introduction to Statistical Quality Control, 5th ed. New York: John Wiley & Sons, ISBN 0-471-65631-3
data(vol_sample)
results1<-xrs_gr(vol_sample)
results2<-X_it(results1)
# Type dev.off() function before use Cp_XCp_X(results2, LES=510, LEI=490, mu=500)