Sources
of variability within and between groups
Within Groups
Variability
a) differences amoung
subjects
b) experimental error
- measurement, recording error
Between Groups
Variability
a) differences amoung
subjects
b) experimental error
- measurement, recording error
c) variation in your
independent variable
Maximizing chances
of finding significance
(based on ratio of between
group: within group variance)
Increase Between
Group Difference
-
increase strength of IV?
-
level of treatment of IV?
-
more sensitive operational
definition/measure for DV?
Decrease Within Group
Variance
-
increase control over extraneous
factors
-
decrease subject variance
- change design? - matched or within subject design
-
increase sample size