With the results of xrs_gr followed by previous X_it iterations, the function calculates the X control limits charts, using a data frame with a fixed subgroup size n. In the graph plotting, the function estimates if any value (row or subgroup average) is out of control limits, and returns a list with calculations. Also, gives the R chart and control limits, which will be used in R_it function.
X_it(prev.results)The under control row list for the X chart
The under control row list for the R chart
The out of control row list for the X chart
The iterations number, It is assumed to be the second or later
The original data frame
The under control subset after iteration
The calculated ranges of data.0
The binary values for out of control equal to one and under control equal to zero, for X and R charts
The X chart control limits vector
The R chart control limits vector
The X chart control limits vector
The R chart control limits vector
The same results in a phrase as the bin values
Is a list of previous results obtained by the xrs_gr function in the first iteration, or a list of results obtained in further iterations by the X_it function.
Erick Marroquin
The function stops if the X chart is under control already, and also stops if there is not any active graphic device.
Montgomery, D.C. (2005) Introduction to Statistical Quality Control, 5th ed. New York: John Wiley & Sons, ISBN 0-471-65631-3
xrs_gr, R_it, Cp_X, we_rules
data(vol_sample)
results1<-xrs_gr(vol_sample)
results2<-X_it(results1)
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