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#1 2008-11-05 17:36:00

azalealmnt
Member
Registered: 2008-11-05
Posts: 1

Probability

A container has 50 marbles. 22 are blue, 11 are red, 8 are yellow, and the rest are white. Suppose we sample 5 marbles in a row, with replacement.

a) What is the probability that exactly 4 of them are blue?

b) What is the probability that at least one is yellow?

c) What is the probability that fewer than 2 are white?

d) How many would you expect to be red?



Any help would be greatly appreciated!
big_smile

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#2 2008-11-05 20:09:41

All_Is_Number
Member
Registered: 2006-07-10
Posts: 258

Re: Probability

For a, I would use the binomial distribution on all of them.

a) Let "drawing a blue marble" be a success, and drawing a marble that's not blue be a failure.

b) Let success be not yellow, and then take the compliment of five successes.

c. Success: white marble. Take sum of probability of zero and one successes.

d) Success is a red marble. Find the mean. (The binomial distribution has a very neat and easy formula for obtaining the mean. It's in your textbook, or a search will reveal it on this site.)


You can shear a sheep many times but skin him only once.

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#3 2008-11-06 07:53:15

azalealmnt
Member
Registered: 2008-11-05
Posts: 1

Re: Probability

I got all of them except c). Thanks for your help!

:3

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#4 2008-11-06 08:34:51

All_Is_Number
Member
Registered: 2006-07-10
Posts: 258

Re: Probability

azalealmnt wrote:

I got all of them except c). Thanks for your help!

:3

You're welcome.

What answer did you give for C?


You can shear a sheep many times but skin him only once.

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