A health psychologist was researching the role of choice in food consumption. In one experiment, the psychologist offered a group of children a choice of either a chocolate chip cookie or fresh fruit. Earlier results indicate that 63% of children choose the chocolate chip cookie. If the earlier results are accurate, and the psychologist randomly picks 4 children to interview after the experiment, what is the probability that exactly 2 of the children chose the chocolate chip cookies? Write your answer as a decimal rounded to the nearest thousandth____.
Q. A health psychologist was researching the role of choice in food consumption. In one experiment, the psychologist offered a group of children a choice of either a chocolate chip cookie or fresh fruit. Earlier results indicate that 63% of children choose the chocolate chip cookie. If the earlier results are accurate, and the psychologist randomly picks 4 children to interview after the experiment, what is the probability that exactly 2 of the children chose the chocolate chip cookies? Write your answer as a decimal rounded to the nearest thousandth____.
Use Binomial Probability Formula: Use the binomial probability formula: P(X=k)=C(n,k)⋅(p)k⋅(1−p)(n−k) Here, n=4 (number of children), k=2 (number of children choosing cookies), and p=0.63 (probability of choosing cookies).
Calculate Combination C(4,2): Calculate C(4,2) using the combination formula C(n,k)=k!(n−k)!n!.C(4,2)=(2!⋅(4−2)!)4!C(4,2)=(2⋅1⋅2⋅1)(4⋅3⋅2⋅1)C(4,2)=6
Calculate (0.63)2: Calculate (0.63)2 for the probability of 2 children choosing cookies.(0.63)2=0.63×0.63(0.63)2=0.3969
Calculate (1−0.63)(4−2): Calculate (1−0.63)(4−2) for the probability of the other 2 children not choosing cookies.(1−0.63)(4−2)=(0.37)2(1−0.63)(4−2)=0.37×0.37(1−0.63)(4−2)=0.1369
Multiply Values to Find Probability: Multiply all the values together to find the probability.P(X=2)=6×0.3969×0.1369P(X=2)=6×0.05432721P(X=2)=0.32596326
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