Repeated measures Anova and sphericity AWS

Chapter 10 One-Way Within Groups ANOVA

Correlated Independent Variable Levels

Independent t-test to One-way ANOVA

One-way ANOVA

Independent t-test Control

Experimental

Control

C1 . . . Cn

E1 . . . En

C1 . . . Cn

Experimental - 1 Experimental - 2

E11 . . . E1n

DIFFERENT people in EACH cell

E21 . . . E2n

Dependent t-test to Within Groups ANOVA Within Groups ANOVA Repeated Measures

Correlated t-test Time 1

S1 . . . Sn

Time 2

S1 . . . Sn

Time 1

Time 2

Time 3

S11 . . . S1n

S21 . . . S2n

S31 . . . S3n

The SAME people in EACH cell

Independence of Observation Assumption Dependent t-test to Within Groups ANOVA Within Groups ANOVA Repeated Measures

Correlated t-test Time 1

S1 . . . Sn

Time 2

S1 . . . Sn

Time 1

Time 2

Time 3

S11 . . . S1n

S21 . . . S2n

S31 . . . S3n

The SAME people in EACH cell

Observations are NOT independent Sphericity assumption

Sphericity adjustments (Epsilon) Greenhouse-Geisser Huynh-Feldt Lower bound (most conservative) Changes in degrees of freedom ONLY