The production manager for the XYZ manufacturing company is concerned that the customer orders are being shipped late.He asked one of his planners to check the timeliness of shipments.The planner randomly selected 1000 orders and found that 120 orders were shipped late.Construct the 95% confidence interval for the proportion of orders shipped late.
A)[.0999 .1401]
B)[.1135 .1265]
C)[.0619 .1781]
D)[.1011 .1389]

Question

Quizplus · Accepted Answer

The sample proportion of late shipments is 120/1000 = 0.12. Using the formula for a confidence interval for a proportion, the 95% confidence interval is calculated as 0.12 ± 1.96 * sqrt((0.12*(1-0.12))/1000), which results in the interval [0.1011, 0.1389].

The Production Manager for the XYZ Manufacturing Company Is Concerned