PSY 303 Lecture Notes - Lecture 18: A213 Road, A215 Road, A Roads In Zone 2 Of The Great Britain Numbering Scheme
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Factorial design language part 3: when an interaction is present, the main effects (even if statistically significant) may be pointless or inappropriate to interpret. You should not describe the pattern of a main effect if it is qualified by the i(cid:374)tera(cid:272)tio(cid:374) (cid:894)ie. if it is(cid:374)"t always true for all si(cid:373)ple effe(cid:272)ts(cid:895) Report that a (cid:373)ai(cid:374) effe(cid:272)t is prese(cid:374)t, (cid:271)ut do(cid:374)"t i(cid:374)terpret it. A true main effect is the same effect in direction across simple effects. A qualified main effect is a different effect (in direction ) across simple effects. Different in magnitude but in same direction- main effect sis not qualified by this interaction: these main effects are true for all simple effects coffee. Interaction: yes simple effect of drink are different in magnitude only, thus the main -- effect of drink is note qualified by this interaction. And yes simple effect of food are different and magnitude and direction.
