In the attached data, I want to do an ANOVA analysis with MathSS as Y, and School Name as X. The variance between groups are not equal, after the "unequal variance" test. Can I still proceed with means comparison such as HSD Tukey? How reliable is this post hoc test? Thank you so much!
Use the Fit Y by X platform to explore as you have started to do. Use the quantiles option to compare the quantiles (important measures for test scores - in my opinion), consider non-parametric tests if you must have p-values. Consider the ANOM with transformed ranks to compare across all schools.