Question

You are working in a small, student-run company that sends out merchandise with university branding to alumni around the world. Every day, you take a sample of 50 shipments that are ready to be shipped to the alumni and inspect them for correctness. Across all days, the average percentage of incorrect shipments is 5 percent. What would be the upper control limit for a p-chart?a. 0b. 0.05c. 0.03082207 d. 0.142466

Answer 1

0.142466 would be the upper control limit for a p-chart

Solution:

Given ,

Sample of 50 shipments

Average percentage of incorrect shipments = 5%

( ESD = $\sqrt{( Pbar( 1-Pbar ) / sample size)}$

        = $\sqrt{( 0.05( 1- 0.05 ) / 50)}$

       = 0.03082207 ( Remove square root )

UCL = Pbar + ( 3 * ESD)

= 0.05 + (3 * 0.03082207)

= 0.14246621