qcc in R Studio, summary does not return sd

Question

I have the following code;

ndata <- rnorm(n=1000,mean=0,sd=1)
qccobj<-qcc(ndata,type="S",sizes = 5,nsigmas=3.0, plot = FALSE)
summary(qccobj)

and for some reason the summary isn't the sd, LCL or UCL;

Call:
qcc(data = ndata, type = "S", sizes = 5, nsigmas = 3, plot = FALSE)

S chart for ndata 

Summary of group statistics:
      Min.    1st Qu.     Median       Mean    3rd Qu.       Max. 
-3.1064844 -0.6892027 -0.0246612 -0.0349110  0.6090715  2.9194738 

Group sample size:  5
Number of groups:  1000
Center of group statistics:  -0.03491101
Standard deviation:  NA 

Control limits:
 LCL UCL

Any ideas as to why?

Answer 1

Have a look at the qcc code on github here . Or enter qcc::summary.qcc in the console to print the summary method in qcc . It will tell you what the code prints to the console as the summary. Note that the limits are a parameter to pass to the qcc function and you do not do so in your example. That's why there are no values printed for UCL and LCL in the summary. qcc either takes limits or the std.dev as parameters. Not both. You could write your own summary method.