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Probability modelling question

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Claire Blair

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Nov 18, 2007, 6:46:40 AM11/18/07
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I have a basic question, which I hope someone can answer for me.

I have sample data that consists of binary (Yes/No) data. The Yes's
correspond to a 'success' event, and the No's correspond to a 'Failure'
event.

I want to know how I can use the data to model and predict the
probability of a success event.

I think the logistic model is what I should use, but I am not sure.

Please advise.

Nasser Abbasi

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Nov 18, 2007, 8:28:37 AM11/18/07
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"Claire Blair" <no.r...@here.com> wrote in message
news:GZCdnScOP_M5u93a...@bt.com...

I think what you want is to fit a probability distribution to your data?

Assuming your X's (events) are i.i.d. you could try to fit Binomial or may
be Poisson? (but with Poisson, we need n to be large and p very small to get
good approximation to the binomial).

So, For Binomial, using Maximum likelihood, p comes out to be X_bar, i.e.
the probability which maximizes the likelihood of observing your data is
this probability. (X_Bar is the mean of the sample data). For Poisson,
also using Max. likelihood, p is X_bar.

Now you can use your 'model' distribution with the above parameter to
calculate other probabilities.

Nasser


richar...@comcast.net

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Nov 18, 2007, 12:08:02 PM11/18/07
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On Sun, 18 Nov 2007 11:46:40 +0000, Claire Blair <no.r...@here.com>
wrote:

Assuming that by "model" you mean you have explanatory variables that
you think help predict success or failure, then yes, a logistic model
(or a probit) is appropriate.
-Dick Startz

deepa....@gmail.com

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Nov 19, 2007, 4:06:37 AM11/19/07
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On Nov 18, 10:08 pm, richardsta...@comcast.net wrote:
> On Sun, 18 Nov 2007 11:46:40 +0000, Claire Blair <no.re...@here.com>

I think u can do a run test which gives u the probability u are luking
for

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