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A recent study found that 40% of all people over age of 62 wear hearing aids. If a random sample of 5 people over 62 is selected,
find the probability of at least 4 wear hearing aids. (please round off into 3 decimal places).
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At least 4 means 4 or 5.
It is the binomial type probability distribution.
The number of trial n= 5; the probability of the success trial is 40% = 0.4, and the number of success trial is k = 4 and k= 5.
P(4) = = = 0.06144;
P(5) = = = 0.01024.
We want to get the sum P = P(4) + P(5) = 0.06144 + 0.01024 = 0.07168. ANSWER
Solved.
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To see many other similar solved problems, look into the lessons
- Simple and simplest probability problems on Binomial distribution
- Typical binomial distribution probability problems
in this site.