A manager wishes to build a control chart for a process. A total of five (05) samples are collected with four (04) observations within each sample. The sample means (X-bar) are; 14.09, 13.94, 16.86, 18.77, and 16.64 respectively. Also, the corresponding ranges are; 9.90, 7.73, 6.89, 7.56, and 7.5 respectively. The lower and upper control limits of the R-chart are respectively