This plot allows you to see the probability of acceptance at various incoming quality levels.

For the camera data, the three curves representing the three sampling plans are located slightly farther to the right than the original plan with a sample size of 259 lenses. As the sample size decreases (curve moves to the right), a greater probability exists of accepting a poor quality lot than with the original plan.

From the plot, large sample size gives a higher acceptance probability when the lot quality is good and a smaller acceptance probability when the lot quality is poor, compared with smaller sample sizes.