SOLUTION: Question 1:It is known that one out of every three people entering a particular department will make at least one purchase. a)if a random sample of n=5 persons is selected,what i

Question 476620: Question 1:It is known that one out of every three people entering a particular department will make at least one purchase.
a)if a random sample of n=5 persons is selected,what is the probability that:
i)two or more of them will make at least one purchase?
ii)at most four of them will make at least one purchase
b)If a random sample of n=81 persons is selected,what is the approximate probability that:
i)30 or more of them will make at least one purchase?
ii)at most 40 of them will make at least one purchase?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Question 1: It is known that one out of every three people entering a particular department will make at least one purchase.
Binomial Problem with p = 1/3
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a)if a random sample of n=5 persons is selected,what is the probability that:
i)two or more of them will make at least one purchase?::1 - binomcdf(5,1/3,1)
= 0.5391
----------------------------
ii)at most four of them will make at least one purchase::binomcdf(5,1/3,4)
= 0.9959
----------------------------
b)If a random sample of n=81 persons is selected,what is the approximate probability that:
i)30 or more of them will make at least one purchase?:::1-binomcdf(81,1/3,29)
= 0.2751
----------------------------
ii)at most 40 of them will make at least one purchase?:::binomcdf(81,1/3,40)
= 0.9990
==========
Cheers,
Stan H.

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