# Poisson distribution of a Fair Coin?

• Nov 7th 2011, 10:45 AM
blackZ
Poisson distribution of a Fair Coin?
Consider tossing a fair coin 40,000 times. Let X be the number of times heads comes up. Suppose X has Poisson distribution with mean 2.4. Find P(X>=2).

=========
I have no idea how to do this one. This maybe wrong attempt.

http://i1114.photobucket.com/albums/...and%20A/4b.jpg
• Nov 7th 2011, 10:49 AM
mr fantastic
Re: Poisson distribution of a Fair Coin?
Quote:

Originally Posted by blackZ
Consider tossing a fair coin 40,000 times. Let X be the number of times heads comes up. Suppose X has Poisson distribution with mean 2.4. Find P(X>=2).

=========
I have no idea how to do this one. This maybe wrong attempt.

http://i1114.photobucket.com/albums/...and%20A/4b.jpg

The answer is given by 1 - Pr(X = 0) - Pr(X = 1).

Then you use the Poisson pmf to calculate each probability ---> basic calculator work.
• Nov 7th 2011, 10:59 AM
blackZ
Re: Poisson distribution of a Fair Coin?
Sorry. I did not get anything.
• Nov 7th 2011, 11:00 AM
mr fantastic
Re: Poisson distribution of a Fair Coin?
Quote:

Originally Posted by blackZ
Sorry. I did not get anything.

I have told you what to do. If you need more help, you will need to be much more specific than the above comment.
• Nov 7th 2011, 11:02 AM
blackZ
Re: Poisson distribution of a Fair Coin?
Ok, So what are the first steps. I need to get it started.
• Nov 8th 2011, 02:41 AM
mr fantastic
Re: Poisson distribution of a Fair Coin?
Quote:

Originally Posted by blackZ
Ok, So what are the first steps. I need to get it started.

Read post #2! It tells you what to do! What don't you understand!?