Between subject design
Different groups but same measures (DV)
Within subjects design
Same group multiple conditions
More statistics power
Within study design
Statistical power
Within design
Counterbalancing
Latin square
Changing the order of the condition
One way ANOVA
(3+) ONE IV (2+ levels) ONE DV
Independent t-test
2 groups (between)
2 groups repeated (within)
Factorial ANOVA
2 IV
Independence
Observations are not influencing each other, every score is independent of each others.
Homogeneity of variance
Spread between two groups
Sphericity assumption
The consistency between conditions for within subjects design