Year 12s: what will be the first way you research your future options? >>

Poisson Distribution

So, I've had some homework on S1 for poisson distribution but I don't get this one question.
It tells me to find, in terms of e, the probabilities of values 10, 11, 12 etc. I've been given the answers but I'm not entirely sure how i should get to them. Would anyone be able to help?

Reply 1

Kevin De Bruyne

Original post by Saira_98

For a Poisson distribution X with rate (lambda) and for any value x, what is P(X=x)?

In other words, if X ~ Po(lambda), then P(X=x) = ..

It should be in your book somewhere.

Reply 2

Saira_98

Original post by SeanFM

For a Poisson distribution X with rate (lambda) and for any value x, what is P(X=x)?

In other words, if X ~ Po(lambda), then P(X=x) = ..

It should be in your book somewhere.

I get that part, but I get to say "P(X=10) = E^-4 * 4^10/10! but I'm not sure how I'd just express this in terms of e when the answer is E^-4

Reply 3

Kevin De Bruyne

Original post by Saira_98

I get that part, but I get to say "P(X=10) = E^-4 * 4^10/10! but I'm not sure how I'd just express this in terms of e when the answer is E^-4

Then something is missing or that answer is incorrect. :redface:

Reply 4

Zacken

Original post by Saira_98

I get that part, but I get to say "P(X=10) = E^-4 * 4^10/10! but I'm not sure how I'd just express this in terms of e when the answer is E^-4

"in terms of e" can be a constant number multiplies by e raised to some power.

Reply 5

Ayman!

Original post by Saira_98

I get that part, but I get to say "P(X=10) = E^-4 * 4^10/10! but I'm not sure how I'd just express this in terms of e when the answer is E^-4

Well, do you know what the formula for P(X = x)?

Reply 6

Saira_98

The question is basically:
Each month a newsagent receives 15 copies of a monthly magazine, of which 10 have been ordered by customers. The monthly demand for the remaining five copies may be modelled by a Poisson distribution with a mean 4. Let X demote the number of copies that will be sold in a month.
Find, in terms of e, the probabilities that X will take the values 10, 11, 13, 14 and 15. Hence calculate the expected value of X.