HTests for main effects
åFixed effects:
íNull Hypothesis: Ho : m1.
= m2. =
É = ma.
å
i.e. drug type (factor A) has no effect on mean response
íNull Hypothesis: Ho : m.1 = m.2 =
É = m.a
å
i.e. drug dose (factor B) has no effect on mean response
åRandom effects:
íNull Hypothesis: Ho : sA2 = 0
å
i.e. there is no extra variance caused by drug type (factor
A)
íNull Hypothesis: Ho : sB2 = 0
å
i.e. there is no extra variance caused by drug dose (factor B)
HTests for interactions
åNull Hypothesis: Ho: mij + m.. -
mi. -
m.j = 0 for all i,j
H Each
level of factor A affects all levels of B in a similar manner and vice versa. i.e. Drug dose has the same effect
regardless of drug type.
åAlternative: Ha: mij + m..
- mi. -
m.j 0 for some i,j
H i.e. Drug dose 2 has twice the effect for drug type 3 than
for drug type 5
HF-Statistic ˆ used to test for main effects and
interactions