Which of the following patterns on an averages chart that displayed 25 sample averages would reveal an out of control process?
a - sample averages scattered in a seemingly random pattern within the 3-sigma control limits
b - half the sample average above the center line and the other half below the center line
c - the first third of the sample average above the center line, the next third below the center line, and the final third above the center line
d - allof the above (A,B, C) suggest an out of control process