Assume process standard deviation is not known. a) Develop Control Charts and explain if this process is In Control or Out of Control. b) Calculate the Process Capability if the specifications are at 21 5?

Assuming you are producing chairs and then, measuring the weights of chairs. You would like to check if your process is In or Out-of-Control and Capable or Incapable. You took one sample each day last week and observed 4 chairs in each sample. (Days are samples.) You know from the past experience that this process has a standard deviation of one ounce. (Z (sigma limits) =3). Day Monday Tuesday Wednesday Thursday Friday Chair 1 23 23 20 18 18 Weight Chair 2 Chair 3 22 23 21 19 19 20 19 20 20 22 Chair 4 24 24 23 22 20