ANCOVA won me ova'

The primary analysis I used for my fire ant analysis was an ANCOVA. Apparently, this is the standard method of teasing apart background effects for studies like mine where there is one treatment field and one field observed to account for seasonal variation. I found it a little frustrating because, in order to do an ANCOVA, you must first show that the response variable changes in response to the covariate and that there is a significant correlation between the covariate and independent variable. Since I did multiple ANCOVAs on different species of ants and some fit the model and some didn't, I was a bit nervous that I would have to go back to square one and find a new model to analyze the data. However, after some consultation, it turns out that as long as the model is appropriate for some of the other species and the species in question shows some trends towards at least one of the statistical tests for appropriateness of the ANCOVA, then it is ok to use the model. PHEW!

ANCOVA

Multiple players
Unstack the deck
Now deal

~from "The Tao of Statistics" by Dana K. Keller

My learning curve...

While working on my final project this evening, I had a realization. Not only was I having a "friendly" interaction with R, but I actually understood what it was telling me. Working with this program has been a strange conversational evolution. In the beginning, I didn't know how to talk to it and when I haphazardly managed a response from it, I didn't understand what it was telling me. Now, I've learned how to speak the R language (admittedly not fluently!) and the statistical language it spits back at me is making more and more sense everyday.

I also glanced back at some of the preliminary analyses I attempted on my data set before taking this class and it sent a shiver up my spine. It's amazing how far I've come from those frustrated fumblings with JMP 5.1 and SigmaPlot.

It's a good feeling to think that all of those long nights with Verzani, Gotelli, Ellison and R are paying off.

the Wonderful Wiki...

This blog is dedicated to the Wiki.

It has been such a wonderful supplement to the texts and my normal class notes. For someone just learning biostatistics, sometimes the class seems a bit fast paced and I have trouble catching everything. Several times I have found myself needing to solve a problem whose solution I only vaguely remember from something we discussed or an exercise we did in class. Most of the time, I am able to browse the Wiki and find either the answer or a good hint to point me in the right direction.

I appreciate everyone's effort in keeping it up-to-date this semester. It has been a very valuable resource.