I have been reading through some past messages and some people apologize in advance for not being in the loop, but I'm afraid I am not even anywhere near them! I am just a linguist, but one who had ambitions to write a book about how to use statistical programs to analyze data in the field. I am really just looking at very elementary types of statistical procedures (correlation, t-tests, ANOVA, chi-square, regression), not getting into PCA or anything like that. But I have a friend at my university who's a works in statistical research and he turned me on to R. Although the majority of applied linguists in my field use SPSS for statistical analysis, I really liked the idea of R because it would make analysis available to those without big budgets for SPSS, and because my friend convinced me that there were lots of things R could do that SPSS couldn't, especially robust statistics. So what I am trying to do in my book is to show how to do things in SPSS, then show that R can do them just as well or better, and then take my readers a step beyond classical statistics to do robust statistics. It sounds really good in theory but I am floundering! I feel fairly comfortable with R now and understand the help files pretty much (that 'foo' thing really threw me at the beginning!), but I still cannot really understand what to do with R and bootstrapping. Is there anything that could give me more background about how I can do bootstrapping with the R libraries? Something like Robust R for dummies? For example, I am working on t-tests right now. I read Wilcox 2003 and saw that he recommended generally 20% means trimming along with percentile bootstrapping for comparing means. But I looked through boot and robustbase and couldn't figure out how to do a one-sided or independent-samples or paired-samples t-test using anything in those robust libraries, and I couldn't see that any incorporated 20% means trimming. So I directed my readers to go with Wilcox's functions, which aren't in R and have to be downloaded into R (no big deal, we can do that, not so complicated). But I'm working on trying to figure out how to do a one-sided t-test with Wilcox's functions, and it hits me--I probably CAN do this in boot, I would just need to have the function that would do 20% means trimming! I conceptually understand 20% means trimming, but wouldn't really know how to write my own program for it. And even if I did (say, I pulled a function for it out of Wilcox's code), I couldn't be sure I was doing it correctly. Part of that also relates to the fact that I am not a statistician and the actual mathematical calculations for statistical tests are something I have to remind myself of every time. In other words, I am not really a statistician either. Anyway, I'm not really asking so much for any specific help here as general help. What you guys do is a really hard code to crack for an outsider, but I've been convinced that robust methods will greatly improve our accuracy and power in applied work, and I really want to bring that to the people in my field. I really just don't understand how bootstrapping works computationally (again, I understand it conceptually on a basic level). I can't follow the examples in the boot library examples area. I haven't found a book that really walks me through R with bootstrapping methods. So . . . any ideas out there of a book on robust functions in R for dummies? Thanks for any help you can give. Jenifer Dr. Jenifer Larson-Hall Assistant Professor of Linguistics University of North Texas (940)369-8950
[RsR] Robust R for dummies?
1 message · Jenifer Larson-Hall