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| Question 1116664:  In a given year,  24% of the people in a community use the emergency room at the local hospital.
 A random sample of  26 people is selected.
 A researcher wishes to know the probability that a fixed number of individuals in the sample will have used the emergeny room in the last year.
 
 
 a)   Explain why this situation will involve a binomial probability distribution.
 
 
 b)  Find the probability that in a sample of 26, exactly 9 people used the emergency room.
 
 
 c)  Find the probability that in a sample of 26,  9 or fewer people used the emergency room.
 Answer by stanbon(75887)
      (Show Source): 
You can put this solution on YOUR website! In a given year, 24% of the people in a community use the emergency room at the local hospital. A random sample of 26 people is selected.
 A researcher wishes to know the probability that a fixed number of individuals in the sample will have used the emergeny room in the last year.
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 a) Explain why this situation will involve a binomial probability distribution.
 An "event" is the selection of a person.
 The event results are independent.
 Prob of "success" for each event is the same,0.24
 Each event is either a success or a failure.
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 b) Find the probability that in a sample of 26, exactly 9 people used the emergency room.
 P(x = 9) = 26C9*0.24^9*0.76^17 = binompdf(26,0.24,9) = 0.0777
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 c) Find the probability that in a sample of 26, 9 or fewer people used the emergency room.
 P(0<= x <=9) = binomcdf(26,0.24,9) = 0.9279
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 Cheers,
 Stan H.
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