Re: Dealing with non-normal, ordinal data for 2-way ANOVA with interactions

2007-03-15 Thread John Gerlach
bject:= Re: [ECOLOG-L] Dealing with non-normal, ordinal data for 2-way ANOVA with = interactions=0A=0A=0A>You seem a trifle sensitive about models and modeling= - statistics =0A>are just tools.=0A=0AFully agree..but these tools tha= t have to be applied correctly.=0A=0A> It makes no sen

Re: Dealing with non-normal, ordinal data for 2-way ANOVA with interactions

2007-03-14 Thread Highland Statistics Ltd.
>You seem a trifle sensitive about models and modeling - statistics >are just tools. Fully agree..but these tools that have to be applied correctly. > It makes no sense to say that something is wrong with the data. I see data sets all the time that are wrong; mistakes, typos, wrong coding

Re: Dealing with non-normal, ordinal data for 2-way ANOVA with interactions

2007-03-14 Thread Anon.
Bahram Momen wrote: > Highland Statistics Ltd. wrote: > >> >Date:Mon, 12 Mar 2007 15:35:18 -0700 >> >From:John Gerlach <[EMAIL PROTECTED]> >> >Subject: Re: Dealing with non-normal, ordinal data for 2-way ANOVA >> with interactions &

Re: Dealing with non-normal, ordinal data for 2-way ANOVA with interactions

2007-03-14 Thread John Gerlach
I agree completely with the tool analogy and with using the correct tool fo= r the data. As I mentioned before, the scale of the data is not always obvi= ous after you have run the experiment. Do you analyze population size data = inflated with zeros as a continuous or a bivariate response data?=0A

Re: Dealing with non-normal, ordinal data for 2-way ANOVA with interactions

2007-03-14 Thread Swalker
Statistics are just tools. Using the best tool for the job is what's being discussed here. If a statistical technique is more powerful than another, models the data on it's natural scale, and can do all of the things ANOVA can do why not use it. That would, at least to me, seem a much more ef

Re: Dealing with non-normal, ordinal data for 2-way ANOVA with interactions

2007-03-14 Thread Bahram Momen
Highland Statistics Ltd. wrote: > >Date:Mon, 12 Mar 2007 15:35:18 -0700 > >From:John Gerlach <[EMAIL PROTECTED]> > >Subject: Re: Dealing with non-normal, ordinal data for 2-way ANOVA > with interactions > > >My short answer is that for controlled

Re: Dealing with non-normal, ordinal data for 2-way ANOVA with interactions

2007-03-14 Thread John Gerlach
You seem a trifle sensitive about models and modeling - statistics are just= tools. Nearly every modern text book clearly points out that ANOVA, regres= sion, etc are specific applications of a general mathematical approach but = that each is a tool designed for a particular purpose. So, yes they

Re: Dealing with non-normal, ordinal data for 2-way ANOVA with interactions

2007-03-13 Thread Highland Statistics Ltd.
>Date:Mon, 12 Mar 2007 15:35:18 -0700 >From:John Gerlach <[EMAIL PROTECTED]> >Subject: Re: Dealing with non-normal, ordinal data for 2-way ANOVA with interactions >My short answer is that for controlled blocked factorial experiments where = >interactions are im

Re: Dealing with non-normal, ordinal data for 2-way ANOVA with interactions

2007-03-12 Thread John Gerlach
seems to be the most ef= ficient.=0A=0A=0A- Original Message =0AFrom: Swalker <[EMAIL PROTECTED] COM>=0ATo: [EMAIL PROTECTED]: Monday, March 12, 2007 11:30:3= 9 AM=0ASubject: Re: [ECOLOG-L] Dealing with non-normal, ordinal data for 2-= way ANOVA with interactions=0A=0A=0AThis is an

Re: Dealing with non-normal, ordinal data for 2-way ANOVA with interactions

2007-03-12 Thread Swalker
e ---- >> From: Highland Statistics Ltd. <[EMAIL PROTECTED]> >> To: ECOLOG-L@LISTSERV.UMD.EDU >> Sent: Sunday, March 11, 2007 4:38:10 AM >> Subject: Re: [ECOLOG-L] Dealing with non-normal, ordinal data for >> 2-way ANOVA with interactions >> >&g

Re: Dealing with non-normal, ordinal data for 2-way ANOVA with interactions

2007-03-11 Thread Highland Statistics Ltd.
ata - failure time approaches don't lend themselves >to factorial ANOVA. > >John Gerlach > > > >- Original Message >From: Highland Statistics Ltd. <[EMAIL PROTECTED]> >To: ECOLOG-L@LISTSERV.UMD.EDU >Sent: Sunday, March 11, 2007 4:38:10 AM >Su

Re: Dealing with non-normal, ordinal data for 2-way ANOVA with interactions

2007-03-11 Thread Nadav Nur
TED] Sent: Saturday, March 10, 2007 6:06 AM To: ECOLOG-L@LISTSERV.UMD.EDU Subject: Re: [ECOLOG-L] Dealing with non-normal, ordinal data for 2-way ANOVA with interactions You might also consider permutation-test based ANOVA, which eliminates any need for normality. See the book "Randomization

Re: Dealing with non-normal, ordinal data for 2-way ANOVA with interactions

2007-03-11 Thread Highland Statistics Ltd.
On Wed, 7 Mar 2007 16:19:31 -0500, Ryan Earley <[EMAIL PROTECTED]> wrote: >Help with stubbornly non-normal data > >We have a data set with 2 independent variables and 1 dependent (Gosner >stage for amphibian larvae). Hello, Normality is less important. What about homogeneity? We have tried

Re: Dealing with non-normal, ordinal data for 2-way ANOVA with interactions

2007-03-10 Thread Nirmal Bhagabati
You might also consider permutation-test based ANOVA, which eliminates any need for normality. See the book "Randomization, Bootstrap and Monte Carlo Methods in Biology" By Bryan F. J. Manly, which has a section on this. A two-factorial model is implemented in the program MeV (www.tm4.org), but thi

Re: Dealing with non-normal, ordinal data for 2-way ANOVA with interactions

2007-03-07 Thread Stephen B. Cox
Well - opinions vary on this topic, but, a couple of things to consider in 2-way factorial ANOVA with a non-normal response. 1) ANOVA is robust with respect to deviations from normality, especially with decent sample sizes. (Good ole Central Limit Theorem comes in handy!) So, what is your sample

Dealing with non-normal, ordinal data for 2-way ANOVA with interactions

2007-03-07 Thread Ryan Earley
Help with stubbornly non-normal data We have a data set with 2 independent variables and 1 dependent (Gosner stage for amphibian larvae). We have tried every creative way to transform the data and end up with significant deviation from normality each time. What we'd like to ultimately do is t