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| Question 206540:  Backyard Retreats, Inc, sells an exclusive line of pools, hot tubs, and spas. It is located just off the Bee Line Expressway in Orlando, Florida. The owner reports 20% of the customers entering the store will make a purchase of at least $50. Suppose 15 customers enter the store before 10am on a particular Saturday
 a) How many of these customers would you expect to make a purchase of at least $50?
 b) What is the probability exactly five of these customers make a purchase of at least $50?
 c) What is the probability at least five of these customers make a purchase of at least $50?
 d) What is the probability at least one customers make a purchase of at least $50?
 
 Answer by stanbon(75887)
      (Show Source): 
You can put this solution on YOUR website! The owner reports 20% of the customers entering the store will make a purchase of at least $50. Suppose 15 customers enter the store before 10am on a particular Saturday ----------------------
 The problem is binomial with p = 0.2, and n= 15
 a) How many of these customers would you expect to make a purchase of at least $50?
 mean = np = 15*0.2 = 3
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 b) What is the probability exactly five of these customers make a purchase of at least $50?
 P(x+5) = 15C5(0.2)^5(0.8)10 = 0.1032
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 c) What is the probability at least five of these customers make a purchase of at least $50?
 P(5<=x<=15) = 1-binomcdf(15,0.2,4) = 0.1642
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 d) What is the probability at least one customers make a purchase of at least $50?
 P(at least one) = 1 - P(none)
 = 1 - binompdf(15,0.2,0) = 0.9648
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 Cheers,
 Stan H.
 
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