Hi everyone, as you can see this is my first post. I should start by saying that my stats is so rusty that I'm not even sure if this is a basic or advanced problem! Anyway, here goes:
I have a very large sample (~30,000,000) of particles of a known size distribution (split into 5 fractions) from which I want to pick a smaller sample (~30,000), and determine the probability of getting various different size distributions. If the original sample of
M particles consists of
A, B, C, D and
E particles in each size fraction, and I am picking
m particles, the probability of picking
a, b, c, d and
e particles is:
First of all, I hope that this is correct! As I said, my stats is very rusty. The problem with this is that, for example,
B is 850,000 and
b is 850, which is beyond the realms of Excel's calculations. Even worse,
B<
C<
D<
E!
So, my question is: is there an approximate method I could use in this case that would avoid these enormous numbers?
I hope I have explained my problem properly! Thank you in advance for any help you can give.