Hi group, I have to design the paired ttest for multiple subgroups for 80 patients with tumor and their respective normal samples. I am new to using multiple groups and I have normally used just tumor versus control. Subgroups: Group(160)- Tumor(80), Normal(80) Gender(80)- Female(27), Male(53) Stage(80)- I(4), II(7), III(54), IV(15) Waiting for your suggestion on design, Thanks, Viritha [[alternative HTML version deleted]]