Hi, I have an experiment where I measured two times the dependent variable (called <b>Intention</b>). So, I have IntentionPre and IntentionPost. I am working with an anova for an independent variable called <b>NumberOfModules</b>. The problem is that if I run the aov(intentionpre~NumberOfModules) I have that there is a significant difference between the means. I want to know the difference between pre and post intentions based on the NumberOfModules. So, I've been told that I should make an ancova and the IntentionPre variable will work as a covariable, but I don't really know how should organize my data in order to get that. My dataframe currently has the following columns: <b>Email (userId), Intention (pre+post values), constrast (is it pre or post value?), and NumberOfModules.</b> What I would do if there were no significant difference between the means for the <b>intentionpre</b>, would be: <i>aov(intention~constrats*NumberOfModules+Error(Email/constrats), gdataframe)</i> What I was thinking to do is adding a column with <b>IntentionPre</b> (duplicated for every pre and post value for the <b>Intention</b> column) and running it like: <i>aov(intention~intentionPre + constrats*NumberOfModules+Error(Email/constrats), gdataframe)</i> Is that a correct reasoning? Any help would be great!!
Camilo V [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.