Warren, and Bill, et al., I have also been intrigued by the kinds of replies. I took a completely different approach and would like to see what people think. First, of course, we should know what the question is. But, I assumed that, considering the data, the question had to do with where the organism occurred, and with its abundance. Those are two very different questions.
I suggested that presence/absence will answer the WHERE question, but may not answer the ABUNDANCE question. After all, information about where something is may often NOT be found where something is NOT. So, I recommended using the presence - absence in one analysis, and where the organism existed in the abundance analysis. Also, I was taught to have the analysis planned prior to data collection as well. Cheers, Jim Warren W. Aney said the following on 14/Jan/08 01:11: > Bill, are we the Luddites in this arena? I agree with you, and my > statistics professor would have taken it one important step further: Choose > your statistical analysis methods before you start collecting your data -- > that way you can carry out your data collection so as to fit your chosen > statistical procedure. Too many people collect their data first, then > search for a statistical procedure that will fit their data. > > The best time to seek the advice of a statistician is before you design your > study, not after you've collected your data. > > Warren W. Aney > Senior Wildlife Ecologist > Tigard, Oregon > > -----Original Message----- > From: Ecological Society of America: grants, jobs, news > [mailto:[EMAIL PROTECTED] Behalf Of William Silvert > Sent: Sunday, January 13, 2008 1:57 PM > To: [email protected] > Subject: Re: Data set with many many zeros..... Help? > > > One point about the various replies to this and other posts that disturbs me > is the focus of the responses. It used to be that statistical questions were > answered in terms of statistical techniques, such as regression or ANOVA or > t-tests. Now the answers are phrased in terms of software - SAS, R, SysStat, > etc. I am not confident that relying on proprietary black boxes is the best > way to analyse data. > > Bill Silvert > > > ----- Original Message ----- > > >> If you have access to SAS, ... >> -- James J. Roper, Ph.D. James J. Roper Ecologia, Evolução e Dinâmicas Populacionais de Vertebrados Terrestres ------------------------------------------------------------------------ Caixa Postal 19034 81531-990 Curitiba, Paraná, Brasil ------------------------------------------------------------------------ E-mail: [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> Telefone: 55 41 33857249 celular: 55 41 99870543 ------------------------------------------------------------------------ Ecologia e Conservação na UFPR <http://www.bio.ufpr.br/ecologia/> Home Page <http://jjroper.googlespages.com> Ars Artium Consulting <http://arsartium.googlespages.com> ------------------------------------------------------------------------
