Question 760642: Not sure on the proper formula to use on the following
at Least Once Problem:
meeting at least one left handed person in eight random encounters on campus when the incident rate is 11% (11 in 100 are left handed).
Please give step by step as I am trying to understand what to look for and how to break out in formula in preparation for test.
Thank You.
Found 2 solutions by stanbon, solver91311:
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! the proper formula to use on the following
at Least Once Problem:
meeting at least one left handed person in eight random encounters on campus when the incident rate is 11% (11 in 100 are left handed).
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Binomial Problem witn n = 8 and p(left) = 0.11
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P(at least one left handed) = 1 - P(no left handed)
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= 1 - 0.11^8
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= 1 - 0.0000000214
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Cheers,
Stan H.
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Answer by solver91311(24713)  (Show Source):
You can put this solution on YOUR website!
What you need is the probability of meeting 1 plus the probability of meeting 2 plus...all the way up through 8.
The probability of  successes in  trials where  is the probability of success on any given trial is given by:
\ =\ {{n}\choose{k}}\left(p\right)^k\left(1\,-\,p\right)^{n\,-\,k})
Where  is the number of combinations of things taken at a time and is calculated by !})
So you need to calculate for  ,  , and  , then  , , and , then  , and so on up through 8, then add all of the results.
There is a much easier way though. You see, the probability of "at least 1" is the same as 1 minus the probability of none. So calculate:
Where  , , and  and then subtract the result from 1.
John
Egw to Beta kai to Sigma
My calculator said it, I believe it, that settles it
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