Question: Consider this: You have a process that exhibit the following:
R(bar)=2.5 with LCL(R)=0, UCL(R)=5.5 and X(bar-bar)=72 with LCL (X-bar)=70.5, UCL(X-bar)=73.5
The current chart shows 5 samples: for R: 3.1, 2, 2.7, 1.9, and 2.9; and for X(bar): 71.5, 71, 71.9, 73, 72.5.
An operator comes to your office giving you 6 new samples that are taken recently for which:
the R samples are: 1.5, 2.5, 3.7, 1.8, 3.1, 2.8 and the X(bar) samples are: 72.5, 73, 72.2, 72.8, 71.1, 71.8.
Which of the following is TRUE?
a. Process is in control but we need to monitor the process
b. Process is somewhat in control but we need to take more samples to make sure
c. Process is in control and no action is needed
d. Process is not in control and we need to take action.