I'm working with some data in which I'm looking for mean differences across 15 subject categories of data on a variable (Clicks) that also covaries with another (Time). I'm trying to control for Time to neutralize its effect on the mean differences in which I'm interested.

I've hit a bit of a road block, however, in that when I run the ANCOVA, my Levene's Test is significant (see attached).

Everything I've read suggests this is a major violation of the ANCOVA's assumptions, but given that I have a large sample size (n=500), can I proceed anyway?

If not, is there another workaround? Eliminating outliers or combining categories (where appropriate)?

ANCOVAs are pretty much the outer limit of my statistical knowledge at this point.

Any guidance would be greatly appreciated.

Thanks,

Jordan