Recently a shipping company took 30 samples of the delivery times of packages that it was responsible for. Each sample was of 100 packages. Out of the 3,000 total packages, 300 were delivered late. In setting up a process control chart, what would be the correct upper control limit for the appropriate control chart for these data?
A) 0.19
B) 0.03
C) 0.07
D) 0.13
E) none of the above

Question

Quizplus · Accepted Answer

The upper control limit for a p-chart is given by p + 3√(p(1-p)/n), where p is the proportion of defective items and n is the sample size. In this case, p = 300/3000 = 0.1 and n = 100. Therefore, the upper control limit is 0.1 + 3√(0.1(1-0.1)/100) = 0.19.

Recently a Shipping Company Took 30 Samples of the Delivery