A proportion is an equality of ratio?
2 answers:
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Answer:
a. 0.52 = 52% probability that Linda gives the correct answer to a question.
b. 0.7692 = 76.92% probability that Linda knows the answer
Step-by-step explanation:
Conditional Probability
We use the conditional probability formula to solve this question. It is
In which
P(B|A) is the probability of event B happening, given that A happened.
is the probability of both A and B happening.
P(A) is the probability of A happening.
In this question:
Event A: Supplies the correct answer:
Event B: Knows the answer
A. What is the probability that Linda gives the correct answer to a question?
0.4(knows the answer)
1/5 = 0.2 of 1 - 0.4 = 0.6(guesses the answer). So
0.52 = 52% probability that Linda gives the correct answer to a question.
B. What is the conditional probability that Linda knows the answer, given that she supplies the correct answer?
Intersection of events A and B is knowing the answer and giving the correct answer, which means that
The desired probability is:
0.7692 = 76.92% probability that Linda knows the answer