preceded by is about has_specified_input has_specified_output achieves_planned_objective data transformation ANOVA studentized range distribution false positive rate absence of between group difference hypothesis post-hoc analysis Tukey HSD for Post-Hoc Analysis 1 2 Alejandra Gonzalez-Beltran IMPORTANT: Do Not to confuse the Tukey HSD test with Tukey Mean Difference Test (Bland-Altman test) Orlaith Burke Philippe Rocca-Serra Tukey Honestly Significant Difference (HSD) test is a statistical test used following an ANOVA test yielding a statistically significant p-value in order to determine which means are different, to a given level of significance. The Tukey HSD test relies on the q-distribution. The procedure is conservative, meaning that if sample sizes (the sizes of different study groups) are equal, the risk of a Type I error is exactly α, and if sample sizes are unequal it’s less than α. Tukey's honestly significant difference http://stat.ethz.ch/R-manual/R-patched/library/stats/html/TukeyHSD.html http://www.tc3.edu/instruct/sbrown/stat/anova1.htm#ANOVAprereq study group population expected value between group comparison objective p-value ready for release