I'm a journalist, wondering what questions to ask about a study that contrasted the impact on serum cholesterol of two drugs. This was a 40 dog study: 5 treatment blocks of 4 dogs each, randomized to: a control block, two blocks at different doses of drug1 and two at corresponding doses of drug2. Analysis was 2-factor repeated measures ANOVA on treatment group and sampling time. Linear contrast tests looked at differences between the drugs, and between doses, and found p<.001 for cholesterol differences between one dosage block of drug1, the control block and the similarly-dosed block of drug2.
Data on one of the drug blocks was actually just 3 dogs, because one dropped out. One critic has also claimed that the population variance of cholesterol levels in these dogs is so wide as to cast suspicion on estimates based on the sample variance in these small blocks. Are there any repeated-measure ANOVA mavins who could suggest whether the approach is sufficiently robust to violations of assumptions to preserve the validity of those impressivly low p-values ? Bill Alpert [EMAIL PROTECTED] ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
