# Calculating a hypergeometric problem on my calculator?

TI 84 calculator. I don’t want this method: http://www.stat.luc.edu/StatisticsForTheSciences/P

That’s much more difficult than the method I had before, I just can’t seem to find the one I used before.

Extra info: I believe it has to do with pressing 2nd, VARS, and then Geometpdf/cfd?

• geometpdf( and geometcdf( will give you probabilities based on a geometric distribution, not a hypergeometric distribution. In fact, the calculator has no built-in command for hypergeometric distributions.

You’ll just simply have to use [Math] > Prb > 3:nCr to manually plug into the hypergeometric formula. (Or alternatively, create a program which does this for you, but you’ve already stated you don’t want to do that.)

Example: Find P(1) when N = 12, n = 4, and 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)

So the values should be entered using the following steps:

• Input [(] [(] [3]

• Press [MATH], then press the right arrow key 3 times to select the PRB menu

• Press [3] to select 3:nCr

• Input [1] [)] [(] [9]

• Press [MATH], then press the right arrow key 3 times to select the PRB menu

• Press [3] to select 3:nCr

• Input [3] [)] [)] [÷] [1] [2]

• Press [MATH], then press the right arrow key 3 times to select the PRB menu

• Press [3] to select 3:nCr

• Input [4], then press [ENTER]

The answer of .5090909091 should be displayed.

• Hypergeometric Calculator