An employee of ABC Inc. takes samples of 6 items from a service line at regular intervals. He notes down the and R values for each sample. After going through 60 groups of 6 samples each, he obtains =50 and R-bar=5. Assume normality.
a) What are the control limits for and R chart? Observe whether all the points fall within these limits.
b) Estimate the mean and standard deviation for the process. Also, calculate the ±3 standard deviation limits for the individual data.
c) If the specification data was 51+6, state your inference on the capability of the process to produce within these specifications.