Dear R users, I know that it was considered many times but having searched through dozens of posts I have only added to my confusion. My question is - is it possible to correctly analyse simple mixed (fully)crossed (factorial) 2-way ANOVA?
Assume we have factor A (fixed) and B (random). In the model with an interaction A should be tested against interaction, B and A:B against residual variance. Specifying aov(response~A*B) gives wrong answer (wrong F ratios, especially for fixed term as it's tested using residuals). Specyfying aov(response~A*B+Error(A:B) specifies correct error term for fixed effect, but wrong for random effect. And now I'm a bit confused - is it possible to analyse such data using aov (or any alternative to aov) - or it's better to switch to lme or lmer (which are better for mixed models but are at first difficult to understand for students, especially in terms of random interactions)? Sorry for posting the same/similar question again - maybe at least it would clarify the problem for future visitors. Cheers, sz. -- Szymon Drobniak || Population Ecology Group Institute of Environmental Sciences, Jagiellonian University ul. Gronostajowa 7, 30-387 Kraków, POLAND tel.: +48 12 664 51 79 fax: +48 12 664 69 12 www.eko.uj.edu.pl/drobniak [[alternative HTML version deleted]]
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