Final answer:
To find the probability that the shipment came from the more reliable supplier, we can use Bayes' Theorem. Given the probabilities of shipments coming from each supplier, we can calculate the probability that the shipment came from the more reliable supplier given that 1 part is defective.
Step-by-step explanation:
To find the probability that the shipment came from the more reliable supplier, we can use Bayes' Theorem. Let A be the event that the shipment came from the more reliable supplier, and B be the event that 1 of the parts tested is defective. We want to find P(A|B), the probability that the shipment came from the more reliable supplier given that 1 part is defective.
Using Bayes' Theorem:
P(A|B) = (P(B|A) * P(A)) / P(B)
Given that 70% of the shipments come from the more reliable supplier and 30% from the less reliable supplier:
P(A) = 0.7, P(B|A) = probability of 1 defective part given that the shipment came from the more reliable supplier = binomial probability with n = 20, k = 1, and p = 0.1, P(B) = probability of 1 defective part regardless of the supplier = P(B|A) * P(A) + P(B|A') * P(A')
where A' is the complement of A.
Substituting the values into Bayes' Theorem:
P(A|B) = (binomial probability with n = 20, k = 1, and p = 0.1 * 0.7) / (P(B|A) * P(A) + P(B|A') * P(A'))