Mr. and Mrs. Doran have a genetic history such that the probability that a child being born to them with a certain trait is 7/8. If they have five children, what is the probability that exactly three 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 7/8. If they have five children, what is the probability that exactly three of their five children will have that trait? Round your answer to the nearest thousandth.Answer:
Use Binomial Probability Formula: We need to use the binomial probability formula, which is P(X=k)=(kn)⋅pk⋅(1−p)n−k, where:- P(X=k) is the probability of having exactly k successes in n trials.- (kn) is the number of ways to choose k successes from n trials, which is calculated as k!⋅(n−k)!n!.- p is the probability of success on an individual trial.- (1−p) is the probability of failure on an individual trial.- n is the number of trials.- k is the number of successes.In this case, P(X=k)2 (the number of children), P(X=k)3 (the number of children with the trait), and P(X=k)4 (the probability of a child having the trait).
Calculate (k)(n): First, we calculate (k)(n) for n=5 and k=3.(3)=3!⋅(5−3)!5!=((3⋅2⋅1)⋅(2⋅1))(5⋅4⋅3⋅2⋅1)=(2⋅1)(5⋅4)=10(5).
Calculate pk: Next, we calculate pk, which is (87)3.(87)3=87∗87∗87=512343.
Calculate (1−p)(n−k): Then, we calculate (1−p)(n−k), which is (1−87)(5−3).(1−87)(5−3)=(81)2=641.
Multiply Calculated Values: Now, we multiply all the calculated values together to find the probability.P(X=3)=(35)×(87)3×(81)2=10×512343×641.
Perform Multiplication: We perform the multiplication to get the final probability. P(X=3)=10×512343×641=327683430.
Convert Fraction to Decimal: Finally, we convert the fraction to a decimal and round to the nearest thousandth.P(X=3)≈327683430≈0.1047 when rounded to the nearest thousandth.
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