In what circumstanOne of the CTQ's of a certain type of bearing is the internal diameter. We have taken 30 samples of size n=13 and the average of averages (grand average, x-doublebar) is 65.303 and the average of all 30 standard deviations is 0.006. What is the UCL of the s control chart? Three decimals.ces we use s charts instead of R charts? Group of answer choices When the sample size (n) is relatively large (n>10) When the sample size is variable When the process distribution is unkown all of the above both a and c both a and b