Please help me.....
- To: mathgroup at smc.vnet.net
- Subject: [mg91072] Please help me.....
- From: "Dewi Anggraini" <dewi_anggraini at student.rmit.edu.au>
- Date: Tue, 5 Aug 2008 04:03:10 -0400 (EDT)
Hi all I'm an international studentat RMIT University Melbourne. Currently, I'm doing my master degree in Statistics and Operations Research. This following 6 months will be my last semester to finish my master degree. Therefore, I have been doing minor thesis about "estimating unknown parameter of Burr distribution" by using Mathematica. I was wondering if this forum could assist me to detect where I got wrong with my program since it works for Burr distribution in some data but not with my data. Additionally, this program (I attached my program along with my data) also works for non-normal distribution, such as Gamma and Weibull since my data are non-normally distributed and they are closely to gamma and weibull distribution. The data are treatment time of cervical cancer patients in a hospital. Frequently, they come to the hospital in the late satge of cancer, thus the minimum time for the treatment is 2 days and the maximum treatment on the data is 21 days. The following is my program to run MLE of Burr distribution. However, it comes up with "comment" results in finding the coefficient of unknown parameters when I run it. n = 69; x2 = {5, 6, 5.5, 5, 8.4, 4.5, 4, 6, 7, 6, 7, 8, 5.4, 5, 4, 3.5, 4.5, 6.5, 5, 3.5, 5.7, 5.8, 5, 4.8, 4.5, 5.8, 3.2, 6, 4, 6, 7, 6.5, 10.7, 7, 4.7, 7, 8.3, 10, 6.5, 4.9, 3.4, 9, 6, 3.1, 5, 4.8, 4, 6, 6, 5.6, 4.2, 4.3, 4.5, 8.4, 8.6, 5.8, 6.8, 4.8, 3.4, 8, 8, 8.3, 8, 4.5, 6, 4.5, 7, 7, 8}; BurrDistribution[x2_, c_, k_] := (c*k)*(x2^(c - 1)/(1 + x2^c)^(k + 1)) pdf = BurrDistribution[x2, c, k] logl = Plus @@ Log[pdf] maxlogl = FindMinimum[-logl, {c, 1}, {k, 2}] mle = maxlogl[[2]] Please assist me in finding the problem I face now. This is very important for my thesis. I look forward for any comments and advices, thank you. Regards, Dewi
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