Mrs. Wheeler prepares a list of 434343 US presidents, 313131 of whom served in the military. Then 888 students each select a president at random (there can be repeats) for their civics presentations.What is the probability that at least one of the students will select a president who did not serve in the military?
Accepted Solution
A:
Answer:
Probability of atleast one of the students(888) selecting a president with no service in the military reaches 1. Step-by-step explanation:
Total Presidents in list = 434343
Military men to be president = 313131
Probability of selecting President who were also military men =
p = 313131/434343 = 0.72
Probability of selecting President who were not military men =
q = 1 - p = 1 - 0.72 = 0.28
Now; no of students who make a choice = 888
no. of Choices made resulting in success = x : {0, 1, 2, 3,............., 888 }
GIVEN CASE:P(f) = Probability of atleast one student selecting a president with no service in military This case fails when no one selects a president with no service in military, let us call it P(f').P(f) = 1-P(f')Calculating P(f'):Let us define:Failure = selecting a president with service in military , p = 0.72Success = selecting a president with no service in military , q = 0.28Using Binomial Theorem:we have this case when n students make selections and x of them are successful. [tex]P(x) = nCx * q^{x} * p^{n-x}[/tex]In case of f' , n = 888 and x = 0[tex]P(0) = 888 C 0 * (0.28)^{0} * 0.72^{888-0}[/tex][tex]= (888!/(888-0)!) * (1) * (0.72)^{888}\\= (0.72)^{888}\\= 2.047655e-127\\[/tex]Hence, P(f') = 2.047655e-127 (reaches 0)Now: P(f) = 1 - P(f')P(f) = 1 - 2.047655e-127 = 1Hence Probability of atleast one of the students(888) selecting a president with no service in the military is 1.