Re: Log-rank & Mantel-Haenszel

2002-02-04 Thread Yan zhou
"R. Stegers" <[EMAIL PROTECTED]> wrote in message news:<a3kc0p$ae3$[EMAIL PROTECTED]>... > I'm trying to understand some medical paper and they used both Log-rank and > Mantel-Haenszel. Could anybody briefly explain what is measured by these > specific test

Re: Log-rank & Mantel-Haenszel

2002-02-04 Thread JJ Diamond
"R. Stegers" <[EMAIL PROTECTED]> wrote in message news:<a3kc0p$ae3$[EMAIL PROTECTED]>... > I'm trying to understand some medical paper and they used both Log-rank and > Mantel-Haenszel. Could anybody briefly explain what is measured by these > specific test

Log-rank & Mantel-Haenszel

2002-02-03 Thread R. Stegers
I'm trying to understand some medical paper and they used both Log-rank and Mantel-Haenszel. Could anybody briefly explain what is measured by these specific tests? Why are they used (in general) en what a calculated value stands for. Thanks in advance,

Log linear models

2002-02-02 Thread janet
Hi everyone, I have this problem and I was wondering whether anyone can help me. I have data on the number of accidents occuring  on two different roads, two different years, three different time periods (of unequal length), given a number  number of vehicles for each occasion. (for example

Re: log-logistic distribution

2001-11-24 Thread Kevin C. Heslin
nd the formula's for the mean and >> variance of a log-logistic distribution. >> >> Thanks in advance, >> >> Kris > > >= >Instructions for joining and leaving this list and remarks about

Re: log-logistic distribution

2001-11-24 Thread David Winsemius
p 37 of www.causascientia.org/math_stat/Dists/Compendium.pdf Kris Bogaerts wrote: > > Dear All, > > I am looking for a reference where I can find the formula's for the mean and > variance of a log-logistic distribution. > > Th

log-logistic distribution

2001-11-22 Thread Kris Bogaerts
Dear All, I am looking for a reference where I can find the formula's for the mean and variance of a log-logistic distribution. Thanks in advance, Kris = Instructions for joining and leaving this list and remarks

Re: log

2001-07-31 Thread Donald Burrill
On 31 Jul 2001, ToM wrote: > what is the opposite of a log?[logarithm] An antilog [properly, antilogarithm]. Equivalently, 10 to that power (if, as in your example, you are taking logarithms to the base 10); or e to that power (if you are taking natural logarithms), which is a

Re: log

2001-07-31 Thread Nadine Wells
ote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > hi > > what is the opposite of a log? > > If you do lg10 of 3 in spss, it gives you a number. how can i take > this number and have as a solution the in

log

2001-07-31 Thread ToM
hi what is the opposite of a log? If you do lg10 of 3 in spss, it gives you a number. how can i take this number and have as a solution the initial one (3) its easy but i cannot remeber = Instructions for joining and leaving

Re: Help Log-Probit in Excel

2001-01-26 Thread Nick Nelson
"H. Noedl" wrote: > Unfortunately my knowledge of statistics is rather limited to the basics > (i.e. regression, t-test etc.). I tried by transforming the drug > concentration into NLog (LN(x)) and the response into probits > (NORMSINV(x)+5) and doing an ordinary linear regression (y=a+bx) to >

Re: Help Log-Probit in Excel

2001-01-25 Thread Richard A. Beldin
This is a multi-part message in MIME format. --46D0737844C9CF0BEDE1D80F Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit I don't know where that came from. I studied from Finney as well. I guess I'm suffering from old-timer's disease. :-) --46D07

Re: Help Log-Probit in Excel

2001-01-24 Thread Rich Ulrich
s popular because it fits many natural models; the math models are powerful; and you don't need a table to look up the logit (log of P over 1-P ). Zero (or 100%) is a problem for either transformation. Folks sometimes adjust their cell-totals by the equivalent of "1/2 of an event.&qu

Re: Help Log-Probit in Excel

2001-01-24 Thread Richard A. Beldin
This is a multi-part message in MIME format. --ECCA490F99BC503A5BC927C1 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit The transform from Z scores to probits uses a constant 6 translation, not 5. I don't know if that solves your problem, but it might elimin

Help Log-Probit in Excel

2001-01-24 Thread H. Noedl
I am a medical Doctor primarily working in malaria research in Thailand. We are doing in vitro tests to assess the drug sensitivity of malaria parasites. For evaluation of the results I use the log-probit model (which is the standard evaluation method for malaria in vitro test) of SPSS 10, which

Re: power analysis for the log-rank test to prove equivalence

2000-06-20 Thread Jerry Hintze
> Does anybody know how to calculate the sample size needed to prove > EQUIVALENCE, not difference of two treatments concerning survival data > (log-rank test, cox regression). > > Thanks Bernd > If you were willing to use proportions or means, you could use our program PASS (a

Re: power analysis for the log-rank test to prove equivalence

2000-06-16 Thread Rich Ulrich
On Fri, 16 Jun 2000 15:03:32 +0200, Bernd Genser <[EMAIL PROTECTED]> wrote: > Does anybody know how to calculate the sample size needed to prove > EQUIVALENCE, not difference of two treatments concerning survival data > (log-rank test, cox regression). "Bio-equivalence&qu

Re: power analysis for the log-rank test to prove equivalence

2000-06-16 Thread Donald Burrill
On Fri, 16 Jun 2000, in reply to Bernd Genser's query > > Does anybody know how to calculate the sample size needed to prove > > EQUIVALENCE, not difference of two treatments concerning survival > > data (log-rank test, cox regression). Robert Dawson wrote: > I

Re: power analysis for the log-rank test to prove equivalence

2000-06-16 Thread Robert Dawson
> Does anybody know how to calculate the sample size needed to prove > EQUIVALENCE, not difference of two treatments concerning survival data > (log-rank test, cox regression). Infinite? The only situation in which I would consider a test as proving the equivalence of two p

power analysis for the log-rank test to prove equivalence

2000-06-16 Thread Bernd Genser
Does anybody know how to calculate the sample size needed to prove EQUIVALENCE, not difference of two treatments concerning survival data (log-rank test, cox regression). Thanks Bernd === This list is open to everyone

Re: Data assumptions in Log-linear models

2000-06-09 Thread Anon.
Bojanowscy wrote: > > Hello > > I would be very grateful if anyone of you could give me (in short) a list of > assumptions about data (dimensions, frequencies in contingency table, > distribution etc) under which one can perform Loglinear analysis (ML > estimation). Log-li

Data assumptions in Log-linear models

2000-06-08 Thread Bojanowscy
Hello I would be very grateful if anyone of you could give me (in short) a list of assumptions about data (dimensions, frequencies in contingency table, distribution etc) under which one can perform Loglinear analysis (ML estimation). ...And, if there are any diffrences, in Logit modelling. I've

RE: Ordinal log-linear model

2000-05-30 Thread Dale Glaser
Re: Ordinal log-linear model It's me again Following your suggestions downloaded LEM. The program is working (I examined featured examples which I downloaded too). I also downloaded zipped manual for LEM. The filename was: MANUAL.PS and in README.TXT was written, that this is a "pos

Re: Ordinal log-linear model

2000-05-29 Thread Buoy
Thank you all. Especially to Jan de Leeuw and Frank Isackson who sent me the PDF version of LEM manual. Again Thank you very much Michal Bojanowski === This list is open to everyone. Occasionally, less thoughtful people

Re: Ordinal log-linear model

2000-05-28 Thread FIsackson
Michal Bojanowski posted (in part) >What is that - POSTSCRIPT viewer / printer? >Or simply >How can I view or print the LEM manual? I suspect that most members of this list know if they have a PostScript printer capable of rendering the LEM manual. For those who do not have such a printer I hav

Re: Ordinal log-linear model

2000-05-28 Thread T.S. Lim
In article <[EMAIL PROTECTED]>, [EMAIL PROTECTED] says... > >In article <8gr7ab$jk$[EMAIL PROTECTED]>, "Buoy" ><[EMAIL PROTECTED]> wrote: > >>Following your suggestions downloaded LEM. The program is >working (I >>examined featured examples which I downloaded too). >>I also downloaded zipped manu

Re: Ordinal log-linear model

2000-05-28 Thread jsuebersax
In article <8gr7ab$jk$[EMAIL PROTECTED]>, "Buoy" <[EMAIL PROTECTED]> wrote: >Following your suggestions downloaded LEM. The program is working (I >examined featured examples which I downloaded too). >I also downloaded zipped manual for LEM. The filename was: MANUAL.PS... > >What is that - POSTSCR

Re: Ordinal log-linear model

2000-05-28 Thread Buoy
It's me again Following your suggestions downloaded LEM. The program is working (I examined featured examples which I downloaded too). I also downloaded zipped manual for LEM. The filename was: MANUAL.PS and in README.TXT was written, that this is a "postscript" format (???) which can be printed

Re: Ordinal log-linear model

2000-05-26 Thread Buoy
Thanks to all of you for all suggestions. I just visited websites you mention and I'm downloading LEM right now. Tomorrow I'm going to work on it. Thanks again Michal Bojanowski === This list is open to everyone. Occasi

Re: Ordinal log-linear model

2000-05-26 Thread John Hendrickx
In article <8gjali$hh1$[EMAIL PROTECTED]>, [EMAIL PROTECTED] says... > Hello to all. > > I'm just studying Masako Ishii-Kuntz's "Ordinal log-linear models" (SAGE > 1994 no.97). > What I wanted to do is to practice fitting by SPSS 8.0 various types of &

Re: Ordinal log-linear model

2000-05-25 Thread Zuwei
ect and column-effect models and also > > uniform association models by SPSS GENLOG procedure. I've got the problem > > with Row-and-Column effects model (RC model), I don't know how to fit it > > using SPSS. > > > > The model for a two-way table is > >

Re: Ordinal log-linear model

2000-05-25 Thread Brendan Halpin
fit it > using SPSS. > > The model for a two-way table is > > LOG(F ) = M + L + L + B*U *V > ij ij i j > > where: > L = lambda > M = constant > B = beta > in standard notation and: > UV > ij > are est

Ordinal log-linear model

2000-05-25 Thread Buoy
Hello to all. I'm just studying Masako Ishii-Kuntz's "Ordinal log-linear models" (SAGE 1994 no.97). What I wanted to do is to practice fitting by SPSS 8.0 various types of models mentioned in the book. There is no problem to fit both row-effect and column-effect mod

Re: log transformation

2000-05-04 Thread Donald F. Burrill
Quick reaction, Rick: For the "statistically challenged" I'd be tempted to try the following; maybe there are reasons you know of in the situation that would make it ... umm ... impolitic. Anyway: It looks as though no one is interested in pursuing interactions among the several categ

Re: log transformation

2000-05-04 Thread Richard M. Barton
Hi Don, Thanks for the response. Comments, clarification, and questions below. --- You wrote: On 3 May 2000, Richard M. Barton wrote: > Suppose Y does not appear to be normally distributed, but Z=ln(Y) does. > > I do a linear regression of Z on X, which is dichotomous (0,1). > > 1) In simp

Re: log transformation

2000-05-03 Thread Donald F. Burrill
On 3 May 2000, Richard M. Barton wrote: > Suppose Y does not appear to be normally distributed, but Z=ln(Y) does. > > I do a linear regression of Z on X, which is dichotomous (0,1). > > 1) In simple terms, what does the unstandardized regression > coefficient b tell me about the relationship

log transformation

2000-05-03 Thread Richard M. Barton
Forgive what may be simplistic questions: Suppose Y does not appear to be normally distributed, but Z=ln(Y) does. I do a linear regression of Z on X, which is dichotomous (0,1). 1) In simple terms, what does the unstandardized regression coefficient b tell me about the relationship between X and

(log-)normal distributions, tests, number of data - I am stuck

2000-05-01 Thread Edzo Wisman
L.S.: I am a graduate student (Drs degree) in finance & investments. I have the following problems and I got stuck. My data are the returns on a quarterly basis of leveraged buyout funds in the USA from 1989 to 1999 (40 quarters). I have bought this data in two groups with in one group funds s

Re: log-Reg and colinearity

2000-03-24 Thread Donald F. Burrill
On Fri, 24 Mar 2000 Llorenç Badiella <[EMAIL PROTECTED]> wrote: > Is it a problem that there exists colinearity between > variables when performing a Log-Reg? If so, how avoid it? It can be a problem, or for that matter several problems. Depends on how severe the collinearity is,

Re: log-Reg and colinearity

2000-03-24 Thread Rich Ulrich
On Fri, 24 Mar 2000 15:28:38 GMT, [EMAIL PROTECTED] wrote: > Is it a problem that there exists colinearity between > variables when performing a Log-Reg? If so, how avoid it? Sure, it is about the same problem as exists for OLS regression. If you really want to *avoid* it, you h

log-Reg and colinearity

2000-03-24 Thread lbadiella
Hi all, Is it a problem that there exists colinearity between variables when performing a Log-Reg? If so, how avoid it? Thanks in advance, Llorenç Badiella [EMAIL PROTECTED] Sent via Deja.com http://www.deja.com/ Before you buy

Power of Log-rank test

2000-02-26 Thread Dr.Wolfgang Hitzl
Dear STATISTICA friends, I cannot figure out the meaning of the survival rate (pi 1 and pi 2) of the log-rank test. (Power Analysis Software). So my questions are: a) How is the log-rank test defined? What does this test actually compare? (The mean of the underlying distribution or the whole

Re: Significance in log-linear models

1999-12-22 Thread Rich Ulrich
On Wed, 22 Dec 1999 11:27:21 +0100, Miguel Verdu <[EMAIL PROTECTED]> wrote: > Why log-linear models can reflect a significant partial association > between factors when none of the cells are significant?. - I'm not 100% sure about your question, but I think the answer is, &q

Significance in log-linear models

1999-12-22 Thread Miguel Verdu
Hi - Why log-linear models can reflect a significant partial association between factors when none of the cells are significant?. Thank you very much Miguel Verdu

Re: Data sample and log normal distribution

1999-11-30 Thread Frank E Harrell Jr
"Donald F. Burrill" wrote: > On Fri, 26 Nov 1999, Frank E Harrell Jr wrote: > > > Beware - you can't just anti-log the mean and s.d. The median > > unlogged value is the antilog of the mean of the logged values. > > That's interesting. The an

Re: Data sample and log normal distribution

1999-11-29 Thread Donald F. Burrill
On Fri, 26 Nov 1999, Frank E Harrell Jr wrote: > Beware - you can't just anti-log the mean and s.d. The median > unlogged value is the antilog of the mean of the logged values. That's interesting. The antilog of the mean of log(X) is the geometric mean of X. Is th

Re: Data sample and log normal distribution

1999-11-26 Thread Donald F. Burrill
On Fri, 26 Nov 1999, Mr. SISAVATH Sourith wrote: > Thanks for the advice. > What I meant about the least square methods is as follows: > If I calculate the mean and the variance of y=log(x) > using the "standard" equations I mentioned in the previous mail > mea

Re: Data sample and log normal distribution

1999-11-26 Thread Frank E Harrell Jr
Beware - you can't just anti-log the mean and s.d. The median unlogged value is the antilog of the mean of the logged values. The mean unlogged value is something like exp(mean unlogged + .5sigma2) where sigma2=sd of logged values. This is also a very assumption-laden approach (logarithm

Re: Data sample and log normal distribution

1999-11-25 Thread Donald F. Burrill
On Wed, 24 Nov 1999, Mr. SISAVATH Sourith wrote: > I have a data sample of grains and the histogram of the > grain size makes me think that the distribution is log-normal. > Is it then reasonable to approximate the density function by a > log-normal distribution, whose variance an

Data sample and log normal distribution

1999-11-24 Thread Mr. SISAVATH Sourith
Hello I have a data sample of grains and the histogram of the grain size makes me think that the distribution is log-normal. Is it then reasonable to approximate the density function by a log-normal distribution, whose variance and mean value has been calculated from the histogram, i.e. mean