> > You know, when I looked at that paper, I did notice their were some > temp/pH combinations that seemed underrepresented and I wondered about the > statistical significance too... > A few thoughts: > First off, I'm really jealous. Someday I'll have enough time/space/$$ to > do something like this. <sigh> > There may only be one or two broods per temp/pH combo, but each of those > broods may have been sizable...Which does leave you open for the possibility > of correlations within the brood (i.e. genetic predisposition based on a > given set of parents, etc.) > Jonathon, when you get your data, I would suggest using a two-way ANOVA > (as probably will anyway) to test for interaction effects (i.e. Temperature > has an effect and pH has an effect, but so does the _combination_ of pH and > Temperature) > As always (and I can say this because of my strong statistics background), > statistics can't actually "prove" anything, but they're about the best tool > we have. > Sorry if this rambled a bit or anyone was brought to tears because of the > references to statistics. <grin> Good luck and keep us informed of how > you're project's going. > >> >> Date: Thu, 14 Dec 2000 14:37:22 -0700 >> From: Mike & Diane Wise <firstname.lastname@example.org> >> Subject: Re: >> >> Jonathan, >> >> I rechecked the reference and you are correct. It shows 17 spawnings. I also >> have their >> preliminary report (Römer & Beisenherz. 1995. Modifikatotrische >> Geschlechtsbestimmung >> durch Temperatur und pH-Wert bei Buntbarschen der Gattung Apistogramma in >> Symposiumband: Fortpflanzungsbiologie der Aquarienfische, Birgit Schmettkamp >> Verlag, >> Bornheim.). In it they used 21 spawns, or about 1500 fry, with tight >> controls (no >> spawns with losses over 10% and extremely precise controls on pH, >> conductivity, & >> temperature). I assume the reason they used acid water conditions was >> because apistos >> prefer breeding in acid water. Spawns in basic water tend to lose >> significant numbers >> of fry. The eggs are laid but they often don't hatch in large numbers. I >> don't know, >> but this may explain why they have no spawns listed for basic water >> conditions. None >> met the 90%+ survival requirement. I am not a statistician so I can't >> comment on that >> part of the paper or why they considered the number of broods sufficient for >> statistical studies. >> >> I, for one, would be very interested in learning your results. Will you be >> maintaining >> consistent conditions from spawning to sexing? If Römer & Beisenherz are >> correct, any >> changes in conditions will change the final results. Please, let me know >> your findings >> when you finish your thesis. They will be valuable evidence to confirm or >> deny Römer & >> Beisenherz's studies. > ------------------------------------------------------------------------- This is the apistogramma mailing list, email@example.com. For instructions on how to subscribe or unsubscribe or get help, email firstname.lastname@example.org. Search http://altavista.digital.com for "Apistogramma Mailing List Archives"!