Mr. and Mrs. Doran have a genetic history such that the probability that a child being born to them with a certain trait is 2/3. If they have five children, what is the probability that at least four of their five children will have that trait? Round your answer to the nearest thousandth.Answer:
Q. Mr. and Mrs. Doran have a genetic history such that the probability that a child being born to them with a certain trait is 2/3. If they have five children, what is the probability that at least four of their five children will have that trait? Round your answer to the nearest thousandth.Answer:
Identify values for formula: Identify the values of n, k, and p for the binomial probability formula.n=5 (the number of children)p=32 (the probability of a child having the trait)We want to find the probability of at least four children having the trait, so we need to calculate the probability for k=4 and k=5.
Use binomial probability formula: Use the binomial probability formula for k=4.P(X=k)=C(n,k)⋅(p)k⋅(1−p)(n−k)Substitute n=5, k=4, and p=32 into the formula.P(X=4)=C(5,4)⋅(32)4⋅(1−32)(5−4)
Calculate binomial coefficient: Calculate the binomial coefficient C(5,4).C(5,4)=4!(5−4)!5!C(5,4)=15C(5,4)=5
Use binomial probability formula: Use the binomial probability formula for k=5. P(X=5)=C(5,5)⋅(32)5⋅(1−32)(5−5) Substitute n=5, k=5, and p=32 into the formula. P(X=5)=C(5,5)⋅(32)5⋅(1−32)(0)
Calculate binomial coefficient: Calculate the binomial coefficient C(5,5).C(5,5)=5!(5−5)!5!C(5,5)=11C(5,5)=1
Calculate probability of at least four children: Calculate the probability of at least four children having the trait.This is the sum of the probabilities for k=4 and k=5.P(at least 4)=P(X=4)+P(X=5)P(at least 4)=24380+24332P(at least 4)=243112
Convert probability to decimal: Convert the probability to a decimal and round to the nearest thousandth.P(at least 4)=243112P(at least 4)≈0.461
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