SOLUTION: From experience, the manager of Kramer's Book Mart knows that 60% of the people who are browsing in the store will make a purchase. What is the probability that among ten people wh

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Question 1188304: From experience, the manager of Kramer's Book Mart knows that 60% of the people who are browsing in the store will make a purchase. What is the probability that among ten people who are browsing in the store, at least five will make a purchase? (Round your answer to four decimal places.)
Answer by ikleyn(52754) About Me  (Show Source):
You can put this solution on YOUR website!
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From experience, the manager of Kramer's Book Mart knows that 60% of the people who are browsing in the store
will make a purchase. What is the probability that among ten people who are browsing in the store,
at least five will make a purchase? (Round your answer to four decimal places.)
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            It is a binomial distribution problem.


The number of trials is 10;  the indexes of successful trials are 5, 6, 7, 8, 9, and 10); 
the probability of success for each single individual trial is p = 0.6.


     The formula to calculate the probability is


         P = P(5) + P(6) + P(7) + P(8) + P(9) + P(10) = sum%28C%5B10%5D%5Ek%2A0.6%5Ek%2A%281-0.6%29%5E%2810-k%29%2Ck=5%2C10%29 = sum%28C%5B10%5D%5Ek%2A0.6%5Ek%2A0.4%5E%2810-k%29%2C+k=5%2C10%29.


     To facilitate my calculations, I used online calculator at this site  https://stattrek.com/online-calculator/binomial.aspx

     It provides nice instructions  and  a convenient input and output for all relevant options/cases.


          The resulting number is P = 0.8337613824 = 0.8338  (rounded as requested).    ANSWER

Solved.

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If you want to see many similar  (or different)  solved problems,  look into the lessons
    - Simple and simplest probability problems on Binomial distribution
    - Typical binomial distribution probability problems
    - How to calculate Binomial probabilities with Technology (using MS Excel)
    - Solving problems on Binomial distribution with Technology (using MS Excel)
    - Solving problems on Binomial distribution with Technology (using online solver)
in this site.

After reading these lessons,  you will be able to solve such problems on your own,
which is your  PRIMARY  MAJOR  GOAL  visiting this forum  (I believe).