Math Is Fun Forum

mom

Member

Registered: 2012-04-25

Posts: 94

Probability

I forgot how to work this out. Can you please help?

In a region, 70% of the population have brown eyes. If 14 people are rondomly selected, find the probability that at least 12 of them have brown eyes. Is it unusual to randomly select 14 people and find that at least 12 of them have brown eyes? Why or why not?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,619

Re: Probability

hi mom,

Welcome to the forum!

This is a binomial situation.  n = 14 and p(brown) = 0.7

Finf P(12), P(13) and P(14) and add them.

If this probablitity is very small you can declare it is unusual.  I suggest you say this if P(answer) < 0.05

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

mom

Member

Registered: 2012-04-25

Posts: 94

Re: Probability

Thank you.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,619

Re: Probability

You're welcome. 

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob