3
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I am having trouble with this Mathematica command:

 Probability[ x + y + z > 14, {x, y, z} \[Distributed] 
 ProductDistribution[{DiscreteUniformDistribution[{1, 6}], 3}]]`

outputs 5 / 54. What I would like to do is use the EmpiricalDistribution sort of like this:

 Probability[x + y + z > 14, {x, y, z} \[Distributed]
 ProductDistribution[{EmpiricalDistribution[{1, 2, 3, 4, 5, 6}], 3}]]

of course, that does not work and just spits out the command. How can I get the Empirical Distribution to work like that?

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2
  • 1
    $\begingroup$ Does this do what you want? Probability[ x + y + z > 14, {x, y, z} \[Distributed] EmpiricalDistribution[{1, 2, 3, 4, 5, 6}] // Thread] $\endgroup$
    – Rojo
    Jan 15, 2014 at 18:38
  • $\begingroup$ Hi Rojo; Yes, that seems to work fine. Thanks. $\endgroup$
    – bobbym
    Jan 15, 2014 at 18:41

1 Answer 1

4
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This is a possibility

Probability[
    x + y + z > 14, 
   {x, y, z} \[Distributed] 
        EmpiricalDistribution[{1, 2, 3, 4, 5, 6}] // Thread
 ]
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5
  • $\begingroup$ that's very interesting. I don't understand what the Thread is doing. Threading the EmpiricalDistribution gives: {DataDistribution["Empirical", {1/6, 1/6, 1/6, 1/6, 1/6, 1/6}, 1, 6], DataDistribution["Empirical", {1, 2, 3, 4, 5, 6}, 1, 6], DataDistribution["Empirical", False, 1, 6]}. Only the middle one of these seems to make sense. $\endgroup$
    – bill s
    Jan 15, 2014 at 20:22
  • $\begingroup$ @bills, the EmpiricalDistribution by itself evaluates to the DataDistribution. Here I am not threading the EmpiricalDistribution but the whole Distributed[{x,y,z},Emp...] (check the precedences). So, just like f[{a, b, c}, 2] // Thread gives {f[a, 2], f[b,2], f[c,2]}, this is equivalent to {Distributed[x, Emp[...]], Distributed[y, Emp[...]], Distributed[z, Emp[...]]} $\endgroup$
    – Rojo
    Jan 15, 2014 at 20:37
  • 1
    $\begingroup$ I get it now! This is saying that x, y, and z are each distributed like the EmpiricalDistribution. The Thread is over the two lines of code, not just over the third line. Thanks for clarifying! $\endgroup$
    – bill s
    Jan 15, 2014 at 21:45
  • $\begingroup$ @bills no problem :) $\endgroup$
    – Rojo
    Jan 15, 2014 at 21:46
  • $\begingroup$ @ bill s; Thanks for asking what I was thinking too. $\endgroup$
    – bobbym
    Jan 16, 2014 at 9:44

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