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**titusland****Member**- Registered: 2010-09-20
- Posts: 9

Hello; please help me with this question:

There are **50** tickets.**3** of them are winning tickets.

Now, I bought **4** out of the 50 tickets.

I want to know the probabilities of

a) **My tickets containing all 3 winning tickets**, and

b) **I do not win anything**.

Thanks in advance.

*Last edited by titusland (2010-09-20 11:12:15)*

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**Fruityloop****Member**- Registered: 2009-05-18
- Posts: 143

Try using the hypergeometric distribution. You have two groups of tickets, winning and losing.

How many ways can you select 0 winning and 4 losing tickets?

How many ways can you select 3 winning and 1 losing ticket?

Use those numbers divided by the total number of ways of selecting 4 out of 50 tickets and you've got your answer!

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**soroban****Member**- Registered: 2007-03-09
- Posts: 452

. .

. .

.

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**titusland****Member**- Registered: 2010-09-20
- Posts: 9

Thanks to both of you for answering this question!

I got it now!

Now, if I had a jar of virtual cookies I'd give you guys some;

but it is mathematically provable that I do not have such a thing.

*Last edited by titusland (2010-09-21 09:21:52)*

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**George,Y****Member**- Registered: 2006-03-12
- Posts: 1,379

Yes, it is a typical hypergeometric problem.

For more teachings on probability distributions,

I would recommend this book*Models for Probability and Statistical Inference: Theory and Applications*

by James H. Stapleton

**X'(y-Xβ)=0**

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**George,Y****Member**- Registered: 2006-03-12
- Posts: 1,379

It is a pity that there are few books explaining useful distributions.

**X'(y-Xβ)=0**

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