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13. A class has 10 students of which 4 are male and 6 are female. If 3 students are chosen at random from the class, find the probability of selecting 2 females using binomial approximation. a) 0.288

User Jassinm
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The answer is 0.432

To find the probability of selecting 2 females out of 3 students chosen at random from a class with 4 males and 6 females, we can use the binomial distribution formula:

P(X = k) = C(n, k) * p^k * q^(n-k)

where:

P(X = k) is the probability of selecting exactly k females,
C(n, k) is the number of combinations of selecting k females out of n total students,
p is the probability of selecting a female (6/10),
q is the probability of selecting a male (4/10),
n is the total number of students chosen (3), and
k is the number of females selected (2).
Substituting the values into the formula, we have:

P(X = 2) = C(3, 2) * (6/10)^2 * (4/10)^(3-2)

C(3, 2) represents the number of ways to choose 2 females out of 3, which is calculated as:

C(3, 2) = 3! / (2! * (3-2)!) = 3

Calculating further:

P(X = 2) = 3 * (6/10)^2 * (4/10)^1

P(X = 2) = 3 * (36/100) * (4/10)

P(X = 2) = 3 * 36/100 * 4/10

P(X = 2) = 432/1000

P(X = 2) = 0.432

Therefore, the probability of selecting 2 females using binomial approximation is approximately 0.432.
User Vriesdemichael
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