A sampling plan states that if 20 incoming transistors are checked and 2 or less defects are found that the lot is accepted. If an incoming lot is 10 percent defective, what is the probability of accepting the lot of transistors?
A) 0
B) 1
C) 0.677
D) 0.333

Question

Quizplus · Accepted Answer

If 20 incoming transistors are checked and 2 or less defects are found, the lot is accepted. Let X be the number of defective transistors in a sample of 20.
Since the lot is 10% defective, the number of defective transistors in a sample of 20 follows a binomial distribution with parameters n = 20 and p = 0.1
P(X ≤ 2) = Σ P(X = i) for i = 0, 1, 2
Using a binomial probability table or calculator, we get P(X ≤ 2) = 0.677
Therefore, the probability of accepting the lot of transistors is 0.677.

A Sampling Plan States That If 20 Incoming Transistors Are