From: Matthew Moss <matthew.moss.coder@...>
Date: 2006-01-08T08:15:30+09:00
Subject: Re: Dice Roller (#61)

On 1/7/06, Christer Nilsson <janchrister.nilsson@gmail.com> wrote:
>
> I have a question regarding the distribution for "(d2)d6".
> In words, I'm first throwing a coin, to decide how many times I will
> throw a the dice.
>
> [1,2] d [1,2,3,4,5,6]
>
> My guess:
>
>   distr("d6")  = [0,1,1,1,1,1,1]             Sum=6
>   distr("2d6") = [0,0,1,2,3,4,5,6,5,4,3,2,1] Sum=36
>
> Probability merge
> distr("d6")     [0,6,6,6,6, 6, 6]             Sum=36
> distr("2d6")    [0,0,1,2,3, 4, 5,6,5,4,3,2,1] Sum=36
>
> distr("(d2)d6") [0,6,7,8,9,10,11,6,5,4,3,2,1] Sum=72
>
> The probability of having one point is P("(d2)d6",1) = 6/72 = 8.3%
>
> Can somebody agree or disagree on this?

Off the top of my head, that seems right.