Forty samples of size 1,000 were drawn from a manufacturing process and the number of defectives in each sample was counted.The mean sample proportion was 0.05.The centerline for the p chart is:
A) 0.05.
B) 50.0.
C) 2.00.
D) 25.0.

Question

Quizplus · Accepted Answer

The centerline for the p chart is the overall proportion of defective items in the process, which is estimated as the mean of the sample proportions. Since the mean sample proportion was 0.05, the centerline for the p chart is also 0.05.

Forty Samples of Size 1,000 Were Drawn from a Manufacturing