Re: Bug with ProbabilityDistribution
- To: mathgroup at smc.vnet.net
- Subject: [mg132540] Re: Bug with ProbabilityDistribution
- From: Bill Rowe <readnews at sbcglobal.net>
- Date: Thu, 10 Apr 2014 03:06:57 -0400 (EDT)
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- Delivered-to: l-mathgroup@wolfram.com
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On 4/9/14 at 4:14 AM, cgillingham1 at me.com (CHARLES GILLINGHAM) wrote:
>Evaluate this:
>ProbabilityDistribution[
>Piecewise[{{0, x1 == 1 && x2 == 1}, {1/2, x1 == 1 && x2 == 0}, {0,
>x1 == 0 && x2 == 1}, {1/2, x1 == 0 && x2 == 0}}], {x1, 0, 1,
>1}, {x2, 0, 1, 1}
>]
>PDF[%][{1, 1}]
>And you get:
>Undefined
>But the probability is obviously 0
>Is there something I am misunderstanding about how simple Boolean
>probability distributions should be set up?
Start with a fresh session and pay attention to the syntax
coloring. Note that x1 and x2 are undefined and your syntax does
not make these local variables. That is entering
f[x_]:=2 x
will cause x to be colored differently than your x1, x2 above.
You get undefined as a result since x1 and x2 are never defined.
- Follow-Ups:
- Variables in ProbabilityDistribution have strange "scoping" mechanism
- From: CHARLES GILLINGHAM <cgillingham1@me.com>
- Re: Bug with ProbabilityDistribution
- From: CHARLES GILLINGHAM <cgillingham1@me.com>
- Variables in ProbabilityDistribution have strange "scoping" mechanism