This OC curve represents a sampling plan developed for a lot size of 1,000, a sample size of 15, and an acceptance number of 2. The probability of acceptance for each of the first six points appears next to the plotted point. What is the average outgoing quality for an incoming fraction defective of 0.25?
A) less than 0.045
B) greater than or equal to 0.045 but less than 0.055
C) greater than or equal to 0.055 but less than 0.065
D) greater than or equal to 0.065

Question

This OC curve represents a sampling plan developed for a lot size of 1,000, a sample size of 15, and an acceptance number of 2. The probability of acceptance for each of the first six points appears next to the plotted point. What is the average outgoing quality for an incoming fraction defective of 0.25? 
A) less than 0.045 
B) greater than or equal to 0.045 but less than 0.055 
C) greater than or equal to 0.055 but less than 0.065 
D) greater than or equal to 0.065

Quizplus · Accepted Answer

Using the OC curve, we can find the corresponding probability of acceptance for an incoming fraction defective of 0.25, which falls between the 0.20 and 0.30 lines on the x-axis. Following the line for a sample size of 15, we can see that the probability of acceptance is approximately 0.06. Therefore, the average outgoing quality is equal to (1 - incoming fraction defective) * probability of acceptance, which is (1 - 0.25) * 0.06 = 0.045. Since this value falls between the ranges of 0.055 and 0.065 on the OC curve, the answer is C.

This OC Curve Represents a Sampling Plan Developed for a Lot