Randy Red's mail-ordering business wants to measure the response time of its operators in taking customer orders over the phone. Red lists below the time recorded (in minutes) from five different samples of the ordering process with four customer orders per sample. Managers want to set control limits that include 99.73% of the sample means. The data you collected is in the table below: Using an R Chart, what are the upper and lower control limits? Sample Fastest Obs. (n=4) Slowest Obs. (n=4) Range (Ri) in difference 1 3.00 10.00 7.00 2 3.00 7.00 4.00 3 1.00 12.00 11.00 4 1.00 7.00 6.00 5 3.00 15.00 12.00 Factors for Computing Control Chart Limits (3 sigma) Sample Upper Lower Size n Range D Range Da 2 3.268 0 3 2.574 0 4 2.282 0 10 5 2.115 0 6 2.004 0