# Math Help - Expect value and standard deviation

1. ## Expect value and standard deviation

Is there a way to calculate these two quantities if I'm throwing two twelve sided die and adding the results that's easier than going through all possible combination and their probabilities?

Thanks.

2. ## Re: Expect value and standard deviation

Originally Posted by kkar
Is there a way to calculate these two quantities if I'm throwing two twelve sided die and adding the results that's easier than going through all possible combination and their probabilities?

Look at this webpage

Scroll down to the fully expanded form of the expression.
That gives you all the impossibles.

For example the term $11x^{14}$ tells us that there eleven ways to roll a sum of fourteen. So the probability is $\frac{11}{144}$ of getting a sum of fourteen.

3. ## Re: Expect value and standard deviation

Thanks Plato!