Question

It is proposed to monitor and control the output of shaft-production machine by drawing samples of six

shafts from the output of the machine every 30 minutes and measuring the diameters of the six shafts. To set up the control chart, data from 20 samples are analyzed to yield the following results: the average (of the average) of the 20 samples = 5.0000 inches, and (ii) the average of the ranges of the 20 samples = 0.2000 inches. The UCL and LCL for the R chart are __