# Knowledge Base

## Solution 12250: Calculating a Hyper Geometric Probability Distribution on the TI-30X IIS/B.

### How do I calculate values for a hyper geometric probability distribution on the TI-30X IIS/B?

There is not a pre-defined function on the TI-30X IIS/B that will find the statistical values for a hyper geometric probability distribution. However, the formula can be entered to find the results. The example below will demonstrate how to find p(1) of a hyper geometric probability distribution.

Example:

What is P(1) if,
N = 12
n = 4
k = 3

Since P(x) = {C(k, x) *C(N-k, n-x)}/C(N, n)

With substitution, P(1) = {C(3, 1) *C(12-3, 4-1)}/C(12, 4)

The values will be input into the TI-30X IIS/B as follows:

1) Input [(] [(] .
2) Press [PRB].
3) Scroll to nCr using the directional arrows. (There will be a line under nCr indicating that function is selected)
4) Press [ENTER].
5) Input  [)] [(] .
6) Press [PRB].
7) Scroll to nCr using the directional arrows and press [ENTER].
8) Input  [)] [)] [÷]  .
9) Press [PRB].
10) Scroll to nCr using the directional arrows and press [ENTER].
11) Input  then press [ENTER].

The displayed answer will show 0.509090909