Chris, check out the article: Variance heterogeneity, transformations, and models of species abundance: a cautionary tale Brian H. McArdle and Marti J. Anderson Can. J. Fish. Aquat. Sci. 61(7): 1294-1302 (2004)
http://pubs.nrc-cnrc.gc.ca/cgi-bin/rp/rp2_abst_e?cjfas_f04-051_61_ns_nf_cjfas7-04 by McArdle an Anderson, they address the back calculation of transformed confidence intervals on page 1296 in the effects of transformations on the model. Apperently in this article you can exponate the confidence intervals to approximate the intervals of the original data, however there are some cautions on interpretations interpretting the mean of the logged data versus the arithmatic mean as log of the arithmatic mean is not the same as the mean of the logged data, depending on the skewness of your orignal data. Mike Colvin Student Contractor Environmental Protection Agency National Health and Environmental Effects Research Laboratory Western Ecology Division 200 SW 35th Street Corvallis, OR 97333 phone: 541-754-4836 "Ecological Society of America: grants, jobs, news" <[email protected]> wrote on 03/21/2006 09:48:44 AM: > Hello all, > > Here's a question that I feel like I should know the answer to... > > I've conducted an ANOVA in sas on a large data set using log(e) > transformed data. I'd like to plot means and 95% CI's using the sas output. > > Is it kosher to simply back-transform the CI's (I have a nagging > feeling that it isn't). Thanks in advance. > > Chris Caudill > > Christopher C. Caudill > Department of Fish and Wildlife Resources > College of Natural Resources > University of Idaho > Moscow, ID 83844-1136 > 208-885-7614 (voice) > 208-885-9080 (fax) > > http://www.cnr.uidaho.edu/UIFERL/Christopher_C._Caudill.htm > > NOTE NEW EMAIL: > [EMAIL PROTECTED]
