I wanna make t-test for effect of gender, another t-test for effect of age, one-way ANOVA for effect of education and MIXED ANOVA (3x8) for another effect? Should I use Bonferroni corection? All is on same dependent variable.
The key point about the multiple testing problem is that every time you have a p-value you have to pay -- like rolling the dice in a casino. A table of p-values needs to be adjusted by the number of tests. Bonferroni is very conservative (i.e., will really lower the adjusted p-values) so you may want to invoke the false discovery rate (FDR) instead -- look up the 1995 paper by Benjamini & Hochberg. But yes, for 2-way and multiway ANOVA, most labs apply a Bonferroni correction.