Math Is Fun Forum

SmileAli

Member

Registered: 2010-04-02

Posts: 10

Probability

A square mesh of wires has a diameter d, and the holes in the mesh are squares whose side length is w. A spherical particle of radius r is dropped on the mesh. What is the probability that it passes through? What is the probability that it fails to pass through if it is dropped n times?
a)
f(x,y) + {1/r, if x^2 + y^2 <= 1 and 0 otherwise.
It would be r^2
How would I solve this? would I find the marginal density?

b)
I was thinking of using binomial distribution to find the probability, since its talking about failure. So, would it be like this?
P(N, n) = (n C N ) * p ^ k * (1-p)^(N-n) would I just show this?

Thanks for your time.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Probability

Hi SmileAli;

I believe you are correct in using the binomial distribution for b).

Can you provide a little more about a)? Where does the problem come from?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

SmileAli

Member

Registered: 2010-04-02

Posts: 10

Re: Probability

a) is referring to: What is the probability that it passes through? Sorry, I should've spaced out the question. Is using the distribution equation (density equation) that I used in my question right? Or do I find the marginal density?

Last edited by SmileAli (2010-04-23 18:47:39)

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Probability

Hi SmileAli;

Went through about 3 hours of sieve analysis. That was supposed to cover your type of problem, but I am sorry I wasn't smart enough to apply it here. Sorry, I just don't know. Maybe someone else can help.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

SmileAli

Member

Registered: 2010-04-02

Posts: 10

Re: Probability

Thank you so much for trying to help! :]