eta squared in ANCOVA versus Gamlj
Posted: Fri Nov 18, 2022 9:03 am
[Update : this should probably be a question filed in the jamovi modules section, since this is a question about the reason for the choices made in developing jamovi (which invariably arise when you teach) rather than a statistics question]
Hi,
I am curious about a difference that can be found between the ANCOVA module and Gamlj: the former reports eta squared values computed via the formula SS effect / (SS effects + SS error) while the latter uses SS effect / SS total.
I am more familiar with the latter formula. What would be the implications of using the former one? Is there a particular reason/context where it would be more natural? Why make a different choice for the two modules?
Here are two screenshots to illustrate my point - same data, basically the same analysis (first with ANCOVA, second with Gamlj): where 0.388 = 48.5/(48.5+10.3+66.2)
and on the other hand where 0.257 = 48.5/(122.7+66.2)
Thanks!
Hi,
I am curious about a difference that can be found between the ANCOVA module and Gamlj: the former reports eta squared values computed via the formula SS effect / (SS effects + SS error) while the latter uses SS effect / SS total.
I am more familiar with the latter formula. What would be the implications of using the former one? Is there a particular reason/context where it would be more natural? Why make a different choice for the two modules?
Here are two screenshots to illustrate my point - same data, basically the same analysis (first with ANCOVA, second with Gamlj): where 0.388 = 48.5/(48.5+10.3+66.2)
and on the other hand where 0.257 = 48.5/(122.7+66.2)
Thanks!