Wednesday, August 6, 2008

PS 47-136: Using plots and copy-paste for rapid introduction to statistics in ecology

Didrik Vanhoenacker, Stockholm University

Background/Question/Methods

Students in our first or second year ecology field courses often analyse real ecological problems. Unfortunately, their ability to evaluate experiments or collected data is sometimes hampered by what they consider scary or tricky statistics. To address this we introduced a two-day crash course in statistics in our ecology courses. We emphasize graphical evaluation of raw data, by using scatterplots and jitter stripcharts rather than regression lines or boxplots. By sorting variables into response or explanatory and into continuous or categorical we provide students with a simple choose-your-test-chart. We focus on the meaning of p-values, but do not introduce standard deviation, t- and F-distributions. We use the free open source software R and what we call copy-paste statistics. On a web site (www.ekolog.se) we have explained R codes that the students easily can copy, modify for their own purpose in a text editor (e.g., Word), and paste back into the R console.

Results/Conclusions

This approach has had tremendous effects. Students no longer fear statistics, they play around with their statistic software at home, and ask for more statistics in the course evaluations. Applicants for the third year course in biological statistics have doubled.