The depth of a keyway is an important part quality characteristic. Samples of size n = 5 are taken every four hours from the process and 20 samples are summarized as follows: Sample X 139.1 10 11 138.4 0.8 2 139.7 14 12 138.5 0.9 140,0 13 13 137.9 1.2 140.1 16 14 138.5 1.1 139.8 0.9 15 140.8 1.0 139.9 10 16 140.5 13 139.7 14 17 139.4 1.4 140.2 12 18 139.9 10 139.3 1.1 19 137.5 15 10 140.7 10 20 139.2 13 (a) Using all the data find trial control limits for X and R charts. Use the coded units. Round your answers to 1 decimal place (e-g. 98.7]. X Control Limits: UCL = i CL = LCL R Control Limits: UCL- CL i LCL=