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 most two 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 most two of their five children will have that trait? Round your answer to the nearest thousandth.Answer:
Identify values n, k, p: Identify the values of n, k, and p for the binomial probability formula: P(X=k)=C(n,k)⋅(p)k⋅(1−p)(n−k). Here, n is the number of trials (children), k is the number of successes (children with the trait), and p is the probability of success on a single trial.n=5 (since they have five children)p=32 (probability of a child having the trait)We need to calculate the probability for k=0, k0, and k1 (at most two children with the trait).
Calculate probability for k=0: Calculate the probability for k=0 using the binomial probability formula.P(X=0)=C(5,0)⋅(32)0⋅(1−32)(5−0)P(X=0)=1⋅1⋅(31)5P(X=0)=1⋅1⋅(31)5P(X=0)=2431
Calculate probability for k=1: Calculate the probability for k=1 using the binomial probability formula.P(X=1)=C(5,1)⋅(32)1⋅(1−32)5−1P(X=1)=5⋅(32)⋅(31)4P(X=1)=5⋅(32)⋅(811)P(X=1)=24310
Calculate probability for k=2: Calculate the probability for k=2 using the binomial probability formula.P(X=2)=C(5,2)⋅(32)2⋅(1−32)5−2P(X=2)=10⋅(94)⋅(31)3P(X=2)=10⋅(94)⋅(271)P(X=2)=24340
Add probabilities for k=0, k=1, k=2: Add the probabilities for k=0, k=1, and k=2 to find the total probability that at most two of the five children will have the trait.P(X≤2)=P(X=0)+P(X=1)+P(X=2)P(X≤2)=2431+24310+24340P(X≤2)=24351Simplify the fraction.P(X≤2)=8117
Convert fraction to decimal: Convert the fraction to a decimal and round to the nearest thousandth.PX≤2 = 8117PX≤2≈0.20987654321Rounded to the nearest thousandth:PX≤2≈0.210
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