--- Begin Message ---
- To: Vidya.Vasuki@asu.edu
- Subject: Re: Joint probability question
- From: Subbarao Kambhampati <rao@asu.edu>
- Date: Mon, 12 Nov 2007 19:55:44 -0700 (MST)
- In-reply-to: <1fe875750711121845o272c3046i96699ea93e21da19@mail.gmail.com>
- References: <1fe875750711121845o272c3046i96699ea93e21da19@mail.gmail.com>
Sorry. That was a word typo. It is supposed to be 2^n - 1
rao
From: "Vidya V" <Vidya.Vasuki@asu.edu>
Subject: Joint probability question
Date: Mon, 12 Nov 2007 19:45:19 -0700
Message-ID: <1fe875750711121845o272c3046i96699ea93e21da19@mail.gmail.com>
Vidya.Vasuki> Hi Dr. Rao,
Vidya.Vasuki>
Vidya.Vasuki> I have a basic probability doubt, please correct me if I am wrong...
Vidya.Vasuki>
Vidya.Vasuki> HW4 contains the following statement:
Vidya.Vasuki> "Given n boolean random variables, we know that explicitly specifying
Vidya.Vasuki> their joint probability distribution takes 2^(n-1) probabilities. "
Vidya.Vasuki>
Vidya.Vasuki> I was thinking may be this should have been (2^n)-1.
Vidya.Vasuki> Two values for each of the n variables makes it 2^n probabilities.
Vidya.Vasuki> And we can find out one of the 2^n probabilities by subtracting the
Vidya.Vasuki> sum of the rest from 1.
Vidya.Vasuki> Hence, (2^n)-1.
Vidya.Vasuki>
Vidya.Vasuki>
Vidya.Vasuki> Thanks,
Vidya.Vasuki> Vidya
Vidya.Vasuki>
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