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Re: WeibullDistribution

• To: mathgroup at smc.vnet.net
• Subject: [mg42462] Re: WeibullDistribution
• From: gohtk at rocketmail.com (goh tat kean)
• Date: Wed, 9 Jul 2003 08:24:34 -0400 (EDT)
• References: <bee0f9$fhd$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Dear Kee,

The formula for the probability density function of the general
Weibull distribution is given in:

http://www.itl.nist.gov/div898/handbook/eda/section3/eda3668.htm

Consider a Weibull PDF with scale parameter of 1 and shape parameter
of 7, you can first define an equation,

<< Statistics`NonlinearFit`
<< Statistics`ContinuousDistributions`
Clear[weif];
weif[x_] := a x^(a - 1) Exp[-(x^a)]

Create some dummy data and plot out the dummy data,

data = Table[{x, 
      a x^(a - 1) Exp[-(x^a)] + Random[Real, {-0.2, 0.2}] /. {a ->
7}}, {x,
      0.1, 1.5, 0.1}];
ListPlot[data]

Fit the dummy data by using NonlinearRegress to obtain a and b,

NonlinearRegress[data, PDF[WeibullDistribution[a, b], x], x, {a, b}, 
  MaxIterations -> 1000000]

Good luck!

Regards,
tat kean

ce.choa.phen.kee at philips.com wrote in message news:<bee0f9$fhd$1 at smc.vnet.net>...
> Hi all,
> 
> I have a set of data, but how can I find out the A and B in 
> WeibullDistribution[ A , B ] ?
> 
> There isn't much informaion regarding the WeibullDistribution provided in 
> the Help Browser. Anyone pls help???
> 
> Thanks in advance.
> 
> regards,
> kee

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  • Re: Re: WeibullDistribution
    • From: Dr Bob <majort@cox-internet.com>