Ruijie <breakaway8 <at> gmail.com> writes: > In my experiment, I expose 10 subjects to 24 different conditions of > stimuli. Each condition is exposed to the same subject 3x. > This would make each subject have 24x3=72 data points. All the subjects > combined would have 72x10=720 data points with each condition having 30 > datapoints. > > To find the grand average of each condition, I find the average of all the > datapoints for a given condition.
[snip] > Since I computed the average of each condition per subject, theoretically, > if i average the average of each condition per subject across all subjects, > the result would be the same as the grand average. > > However, this is not the case when I use R or Excel. regardless of functions > used. Anyone have any thoughts? Nothing obvious springs to mind. We need a reproducible example. How different are the means computed in different ways? Is the difference attributable to round-off error? ______________________________________________ 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.
