Hi all, apologies for seeking advice on a general stats question. I ve run normality tests using 8 different methods: - Lilliefors - Shapiro-Wilk - Robust Jarque Bera - Jarque Bera - Anderson-Darling - Pearson chi-square - Cramer-von Mises - Shapiro-Francia All show that the null hypothesis that the data come from a normal distro cannot be rejected. Great. However, I don't think it looks nice to report the values of 8 different tests on a report. One note is that my sample size is really tiny (less than 20 independent cases). Without wanting to start a flame war, are there any advices of which one/ones would be more appropriate and should be reported (along with a Q-Q plot). Thank you. Regards, -- yianni
gatemaze at gmail.com wrote:> Hi all, > > apologies for seeking advice on a general stats question. I ve run > normality tests using 8 different methods: > - Lilliefors > - Shapiro-Wilk > - Robust Jarque Bera > - Jarque Bera > - Anderson-Darling > - Pearson chi-square > - Cramer-von Mises > - Shapiro-Francia > > All show that the null hypothesis that the data come from a normal > distro cannot be rejected. Great. However, I don't think it looks nice > to report the values of 8 different tests on a report. One note is > that my sample size is really tiny (less than 20 independent cases). > Without wanting to start a flame war, are there any advices of which > one/ones would be more appropriate and should be reported (along with > a Q-Q plot). Thank you. > > Regards, >Wow - I have so many concerns with that approach that it's hard to know where to begin. But first of all, why care about normality? Why not use distribution-free methods? You should examine the power of the tests for n=20. You'll probably find it's not good enough to reach a reliable conclusion. Frank -- Frank E Harrell Jr Professor and Chair School of Medicine Department of Biostatistics Vanderbilt University
yOn Mon, 28 May 2007, Bill Szkotnicki wrote:> Hello, > > I have installed R2.5.0 from sources ( x86_64 ) > and added the package RODBC > and now I am trying to connect to a mysql database > In windows R after installing the 3.51 driver > and creating the dsn by specifying server, user, and password > it is easy to connect with > channel <- odbcConnect("dsn") > > Does anyone know what needs to be done to make this work from linux?Did you not read the RODBC README file? It is described in some detail with reference to tutorials. -- Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595
I have now read the README file which I should have done before. :-[ Sorry. To summarize: - Install the odbc connector driver (3.51) - Set up the dsn in the file .odbc.ini - It works beautifully and RODBC is super! Prof Brian Ripley wrote:> yOn Mon, 28 May 2007, Bill Szkotnicki wrote: > >> Hello, >> >> I have installed R2.5.0 from sources ( x86_64 ) >> and added the package RODBC >> and now I am trying to connect to a mysql database >> In windows R after installing the 3.51 driver >> and creating the dsn by specifying server, user, and password >> it is easy to connect with >> channel <- odbcConnect("dsn") >> >> Does anyone know what needs to be done to make this work from linux? > > Did you not read the RODBC README file? It is described in some detail > with reference to tutorials. >-- Bill Szkotnicki Department of Animal and Poultry Science University of Guelph bszk at uoguelph.ca (519)824-4120 Ext 52253