Please help me solve this problem.
2 answers:
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Answer:
A. 0.1035
B. 0.1406
C. 0.1025
Step-by-step explanation:
Given that:
the number of sample questions (n) = 5
The probability of choosing the correct choice (p) = 1/4 = 0.25
Suppose X represents the number of question that are guessed correctly.
Then, the required probability that she gets the majority of her question correctly is:
P(X>2) = P(X=3) + P(X =4) + P(X = 5)
P(X>2) = [ 0.0879 + 0.0146 + 0.001 ]
P(X>2) = 0.1035
B.
Recall that
n = 5 and p = 0.25
The probability that the first Q. she gets right is the third question can be computed as:
Since, x = 3
P(X=3) = 0.1406
C.
The probability she gets exactly 3 or exactly 4 questions right is as follows:
P(X. 3 or 4) = P(X =3) + P(X =4)
P(X = 3 or 4) = [ 0.0879 + 0.0146 ]
P(X=3 or 4) = 0.1025