The Center Line (P-Bar) for a P-Chart Is 0

Multiple Choice

The center line (p-bar) for a p-chart is 0.50 with an UCL = 0.70 and a LCL = 0.35.The results of the next eight sample means are 0.45, 0.60, 0.39, 0.44, 0.48, 0.53, 0.54, and 0.61.What would you do?

A) Nothing; the process is in control.
B) increase the sample size to get a better measure.
C) investigate assignable causes because four observations are above the center line.
D) investigate assignable causes because there is a bad trend (run) .