Alcoa is making long aluminum rods for the frame of airplanes for the Boeing Company. The current process produces these rods, which need to pass a tensile strength test. Alcoa collected 6 observations every two hours in the first shift. The X-bar's and range are given below:

Sample Number	OBS. 1	OBS. 2	OBS. 3	OBS. 4	OBS. 5	OBS. 6	Mean	Range
1	37.00	37.50	38.50	40.00	39.00	42.00	39.00	5.00
2	38.00	37.00	41.50	39.00	38.50	37.00	38.50	4.50
3	38.50	42.50	41.50	42.00	42.50	42.00	41.50	4.00
4	37.00	42.50	41.00	42.50	42.00	41.00	41.00	4.50

Determine the control limits for the X-chart and the R-chart.