The OC curve should pass through the two designated points to meet the two constraints AOQL and [AFI.sub.L].
Figures 2-4 show the OC curves to depict a comparison of the optimal scheme with other two AOQL contour inspection schemes in CSP-1.
 analyzed the properties of OC curve of the acceptance sampling plans based on gamma-Poisson distribution.
In this paper, we use two points on the OC curve approach to design the RGS plan.
Mayer(1967) suggested that the quality standard 'p' can be considered as a quality level, along with certain other conditions to specify an operating characteristic curve later studied by Soundararajan (1975) as the quality level corresponding to the inflection point of the OC curve. One of the desirable properties of an OC curve is that the decrease of the probability of acceptance should be slower for lesser values of 'p' (good quality level) and steeper for larger values of 'p' (bad quality level), which provides a better overall discrimination.
 Clark.C.R., 1960, "OC curves for ChSp-1, Chain Sampling Plans", Industrial Quality Control 17 (4) pp.10-12
In general however, it is difficult to compute the OC curve
In Section 4, we will compare the efficiency of the proposed RGS plan with the single sampling plan in terms of OC curve
and the average sample number (ASN).
Each OC curve
corresponds to the estimated probability of correct classification and is determined by subtracting the joint probability estimated above from the number one.
The slope of the OC curves
in Figures 1-4, respectively, displays the discriminatory power of the sampling scheme between good and bad lots.
The advantages of the proposed plan over SkSP2 and the reference plan are discussed in terms of ASN, ATI, and OC curves
. The proposed plan is found to be more efficient than these two sampling plans in terms of ASN and ATI.
A simple subjective way to arrive at the "optimum" risks is for an agency and its contractors to examine together the OC curves
for a given acceptance plan.