In a fabric manufacturing factory , the quality control process using control charts from SPC . In an hour there are a total of 5 samples are taken each having 5 observations regarding the thickness...

In a fabric manufacturing factory , the quality control process using control charts from SPC . In an hour there are a total of 5 samples are taken each having 5 observations regarding the thickness of fabric in measured in millimeters . In a particular hour , the sample means (X -bar) are noted to be : 156.46 , 199.62 , 189.31 , 102.22 , and112.09 respectively . In the same sample , the corresponding ranges are : 11.97 , 12.17 , 13.94, 11.8 11.86 , and 11.83 respectively . What are the lower and upper control limits for the R chart ? a . 0, 25.12 b. 0,30.07 c. 0,28.17 d. None is correct e. 0,26.07 f. 0,29.17