434 A First Course in Quality Engineering
Furthermore, the probability P(A or B or C) is calculated as:
P(A ∪ B ∪ C) = P(A) + P(B) + P(C), because A, B, and C are mutually exclusive�
Also, we have assumed independence between events in the two samples,
which may be true when sampling from large lots�
This example shows how to calculate the probability of acceptance for one
value of p = 0�05� Similar calculations can be made for several other values
of p and the primary OC curve drawn from them� The OC curves shown in
Figure 7�8 belong to this sampling plan�
7.7.4 The Average Sample Number of a Sampling Plan
The average sample number (ASN) of a sampling plan is the average num-
ber of units that must be inspected per lot to reach an accept/reject ...