This plot allows you to see the average total number of inspected units at various incoming quality levels.

When the incoming quality level is low enough to cause lots to be rejected, rework and re-inspection must take place to replace the defectives. Therefore, the average number of units that are inspected increases as the lot percent defects increases.

For the grocery bags, when the average incoming quality level is very good, near 0% defective, the sample size is close to what is specified by the sampling plan.

The three curves representing the three sampling plans are located much further to the right than the original plan with a sample size of 306 bags. As the sample size decreases (curve moves to the right), the average total inspection increases.