A cell phone manufacturer inspects the video display on each color phone to verify that the screen can display all colors with the brilliance their customers have come to expect. Each phone is turned on, run through a self-test procedure, and classified as either acceptable or unacceptable based on test performance. Based on historical data, the manufacturer produces 0.1 percent defective displays. If they inspect 5000 phones each day for the next 10 days, what are the upper and lower control limits for their control chart if their sample mean mirrors their historical process average?
A)0.0002, 0.0001
B)0.0142, 0.0058
C)0.1127, 0.0873
D)0.0023, 0.0000

Question

Quizplus · Accepted Answer

The control limits for a proportion chart (p-chart) are calculated using the formula: p ± 3√(p(1-p)/n), where p is the historical defect rate (0.001) and n is the sample size (5000). This results in limits of approximately 0.0023 and 0.0000.

A Cell Phone Manufacturer Inspects the Video Display on Each