Statisitics - Random Variables

[tjackson]

Homework Statement

There is a population of 30 elk. 6 elk are captured, tagged and then released into the wild. Then later 5 elk are captured, what is the probability that k elk are tagged?

Homework Equations

p=6/30 = 1/5P = \stackrel{n}{k} * p^k * (1-p)^k

\stackrel{n}{k} is n choose k

The Attempt at a Solution

plug in the values.

but the big question I have is: Is this a binomial RV?

 

[80past2]

I think this would be hypergeometric.

 

[80past2]

to elaborate, the way you have it, as a binomial, would mean that each deer caught has a 6/30 chance of being tagged. but this is not the case. if you catch a deer and it is tagged, then there are 24 untagged deer and 5 tagged deer remaining. so on your next catch, you would a 5/29 chance of catching a tagged deer. but you can use a hypergeometric distribution on this to make it a little easier.