# Math Help - probability help

1. ## probability help

I have the following two questions. For the first one do I need to know how many games are in an NCAA tournament, and if I do does anyone know this. As for the second question, I don't understand what it is asking for by the wording of it.

1) Assuming the probability of guessing the winner in any NCAA basketball tournament game is 0.5 (that is an even toss-up), what is the probability of picking the winner in all the games?

Would I use (0.5/number of games)

2) What dollar value would be required as a prize for guessing all the winners for your expected value of guessing to be $1? 2. Originally Posted by manyarrows I have the following two questions. For the first one do I need to know how many games are in an NCAA tournament, and if I do does anyone know this. As for the second question, I don't understand what it is asking for by the wording of it. 1) Assuming the probability of guessing the winner in any NCAA basketball tournament game is 0.5 (that is an even toss-up), what is the probability of picking the winner in all the games? Would I use (0.5/number of games) 2) What dollar value would be required as a prize for guessing all the winners for your expected value of guessing to be$1?
For part a. If there are n games played then the probability of guessing all n correctly is $(0.5)^n$.

b) The prize ought to be $\2^n$.

3. ## please explain

Could you explain the rational?

4. Originally Posted by manyarrows
Could you explain the rational?
It is no different from flipping a coin.
If you flip it 4 times the probability of 4 heads is $(0.5)^4$.
That is one out of 16.

5. I saw what you meant by that part. It is funny my textbook actually had the coin flipping example.

I'm still confused on the prize money. This includes not understanding the question as well.

Thanks Plato

It's funny we call one of our 1 year old twins Socrates as a nickname, she will intently stare at things for long periods of time in deep thought. She will then look at you and babble a babytalk lecture at you.

6. Originally Posted by manyarrows
I'm still confused on the prize money. This includes not understanding the question as well.
Frankly I agree with that. ‘Expected value’ is usually done with more that one event.
That is, in this case we expect to have an amount to loose. Say the cost of getting in.
But if it cost nothing to play and the probability of winning is $(0.5)^n$ then if $P$ is the ‘prize’ then the expected value is $(0.5)^n(P)$.

7. ## Thanks

I appreciate the help. I made the mistake of taking a statistics class offered by the economics department instead of one offered through the math department. It's just, here are the formulas, plug in the numbers. When I have time I am going to look into a better text on the subject, since I do see its value. Thanks again.