This capability value is worse than before, and it is the third successive value below 1.33. This improved value may get you off the hook with your boss, but you are likely to remain in trouble with your customer. This dramatic drop from the previous value is sure to trigger an angry reaction. At last, a capability value that is above the target value of 1.33. This is an excellent capability ratio.
Happy days are here again.
Of course, the real answer is that the value is not slipping. Look at the average and range chart for the 100 subgroups of size 5 once again. There is no evidence that the process has changed in any way during these 10 segments. The process was not getting worse, nor was it getting better. But the statistics were changing with each segment even though the process remained the same, and these changes resulted in different values for the centered capability ratio.