I have a basic statistics exam coming up and while studying found the instructor's notes to be a little short in one area.

In the field of linguistics, separate ANOVAs for subjects and items are fairly common to get results that are generalisable for people as well as stimuli.

However, all she wrote about it is (and that's the part I don't understand) that for the VP analysis, the mean per

**subject**and independent variable is calculated (aggregating

**over items**), while for the item analysis, the mean per

**item**and independent variable is calculated (aggregating

**over subjects**). Surely it should be the other way around?

So I guess my question is quite general: how do you aggregate something over items vs over subjects and why is this flipped for the analyses? It's been surprisingly difficult to find anything about this - seems that most people (justifiably) assume that you'd cover that in your intro to statistics class. Which is basically the class I'm having trouble with...

Sorry if the terminology is a bit off, it's translated from German.

Any help would be much appreciated!