Design Basics Flashcards
Statistical Power
The ability to find a statistically significant difference between your experimental conditions (avoid making a type II error in your conclusion).
Improving Statistical Power
Reducing random error (tighten experimental controls, ex: room temp consistent with groups) & decreasing treatment effect (make groups vastly different, 10 mg, 50 mg, 500 mg)
Order Effect
When participants’ responses in the various conditions are affected by the order of conditions to which they were exposed.
The Practice Effect
Improvement on a task due to repetition
The Fatigue Effect
A decrease in performance of a task due to repetition (tired)
The Boredom Effect
a decrease in performance of a task due to boredom due to repetition.
The Carryover Effect
May respond differently depending on which treatment they had prior.
Counterbalancing
Minimizing confounds in a within-subject design, it is used to address order effects.
ABBA (reverse counterbalancing
When subjects experience conditions more than once, they first experience the conditions in one order, and then the reverse order.
Block Randomization
Designed to randomize the condition order for each subject (ex: 1: a, c, b / 2: b, a, c / etc….). After one order, repetition (with randomization) continues. Subjects will experience all conditions before moving to the next randomized order.
Between Group Variability
Treatments, Individual differences, & error
Within Group Variability
Individual differences & error
Between-Subject Designs
Each participant has equal probability of assignment to any one of the experiment conditions; confounds minimized using random assignment.
Between-Subject Advantages
- No carryover effects
- Less likely that participants will catch on to the hypothesis
- Exposure to multiple levels of the IV may be impossible or ethically & practically difficult
Within Subject Designs (repeated measures)
Each participant engages in every experimental condition one or more times; confounds minimized by counterbalancing.
