exam III Flashcards
(49 cards)
confounding variable
a variable that varies along with the independent variable
how to avoid confounds / keep variables constant
experimental control + randomization
internal validity
establishes cause-and-effect relationship
post-test only design
two equivalent groups of participants (experimental + control), IV manipulated, DV measured
pre-test post-test design
a pre test is given before IV manipulation
pre-test advantages / disadvantages
tell whether groups are equivalent
focus on change + individual
dropout factor
dis - sensitization, time-consuming
2 ways to assign participants to conditions
independent groups design
repeated measures design
independent groups design
different individuals participate in each condition, random assignment
repeated measures design (with-in subjects)
same individuals participate in both conditions
practice effect
improved performance as a result of repeated practice
fatigue effect
deterioration in performance because of boredom, fatigue or distraction
carryover effect
effect of first condition influences responses to the second condition
how to deal with order effects?
counterbalancing
straightforward manipulation
Manipulate variable by presenting written, verbal, or visual material
staged (event) manipulation
stage events that occur during the experiment, often use a confederate
ceiling effect
IV appears to have no effect on DV because participants quickly reach maximum level
floor effect
IV appears to have no effect on DV because participants cannot reach higher levels
demand characteristics
features of the study that may inform the participant about the purpose/hypothesis of the study
use filler items / placebo groups
experimenter bias
treating participants differently / making biased recording of behavior
why increase levels of IV?
to provide more info, compare more than two groups, see curvilinear relationships, test for interactions in factorial designs
2 x 2 factorial design
2 IVS w 2 levels each
4 cells
2 x 3 factorial design
2 IVS (2 levels, 3 levels)
6 cells
2 x 2 x 3 factorial design
3 IVS (2 lvls, 2 lvls, 3 lvls)
12 cells
main effects
effect of each IV by itself, as many main effects as there are IVs
