# TI-89 Titanium - Probability - Expected Value

• Calculators
rekshaw
EDIT: I found the solution, it can be done using the TwoVar() function on the TI-89 and it gives you a whole lot more than just the expected value. thanks anyways

Hello everyone! :)

I hope I will get an answer for this!

As a USER-DEFINED function I would like to be able to calculate the Expected Value of n outcomes with their respective probabilities (also in a single matrix)

it should look something like this:

$\begin{pmatrix} 1 & 1/6 \\ 2 & 1/6 \\ 3 & 1/6 \\ 4 & 1/6 \\ 5 & 1/6 \\ 6 & 1/6 \end{pmatrix}$

To find the expected value I would need to do:

$(1 \times 1/6) + (2 \times 1/6) + ... + (6 \times 1/6) = E(X)$

Basically, multiply each outcome with its probability and finally sum the whole lot...

IDEALLY...I would like to be able to make a single 2 x n matrix with outcomes and probabilities side-by-side, store it as A and be able to do:
Code:
expval(A)

or...which is faster to type: make a n*2 matrix!

Anyways...sorry for the long post, any help will be much appreciated!!!!

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