[R-sig-Epi] lognormal distribution in survreg (Mariana Wagner)

[Lazarus Mramba]

Hi Mariana,

The log(scale)=0.40546 output means that if you want to get the scale,
then, you compute the exponential of the coefficients 0.40546 and the
answer will be 1.5
The sclae for the standard error can be found by  computing the
exponential of 0.0594, giving 1.0611996

Is that clear?

Kind regards,


Lazarus Mramba

P.O Box 230, 80108,
Kilifi, Kenya
Mobile No. +254721292370

(office extension : 419)

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Today's Topics:

   1. lognormal distribution in survreg (Mariana Wagner)


----------------------------------------------------------------------

Message: 1
Date: Sat, 04 Aug 2007 09:51:33 +0200
From: Mariana Wagner <marianaw at web.de>
Subject: [R-sig-Epi] lognormal distribution in survreg
To: r-sig-epi at stat.math.ethz.ch 
Message-ID: <1592232557 at web.de>
Content-Type: text/plain; charset=iso-8859-15

I fit a lognormal model to survival data using survreg.  I am confused
about the output, because I do not know how to interprete the
"scale." The output is:

Call:
survreg(formula = surv1 ~ p$score, dist = "lognormal")
               Value Std. Error     z         p
(Intercept)   5.5891     0.1986 28.14 2.76e-174
p$score      -0.0162     0.0102 -1.58  1.14e-01
Log(scale)    0.4046     0.0594  6.81  9.65e-12

Scale= 1.5

Log Normal distribution
Loglik(model)= -996.1   Loglik(intercept only)= -997.4
        Chisq= 2.5 on 1 degrees of freedom, p= 0.11
Number of Newton-Raphson Iterations: 4
n= 505

Is scale the scale parameter of the lognormal distribution ? If yes is
there no estimate of the standard derivation? 

Thanks,

Mariana



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End of R-sig-Epi Digest, Vol 16, Issue 2