13 Experimental Designs Flashcards
steps for experimental research:
1) define pop. 2) select sample 3) assign to groups 4) administer intervention 5) measure outcome
types of assignment
random, matched
minimizes group diff due to chance
matched (good for small n)
what are diff experimental designs?
pre-test/post-test, post-test only, factorial, repeated measures vs. independent groups, multiple dependent variables
measurements of dependent variables before and after intervention, allows msmt of change for individual cases
pre-test/post-test design
problem of pre-test?
may introduce change in behaviour
cons of post-test only?
not strong for test cause and effect
doesn’t measure change in individual but tween control and experimental groups, assume grps initially identical and no change in controls, risky in clinical research
post-test only design
when use post-test only?
when pre-test impossible or unethical or would itself affect outcomes
allows to measure individual and combined effects of multiple independent variables
factorial designs
in factorial design, if all possible combos it is called ___, if some left out, ____
fully crossed; incomplete
repeated measure have ___ power than independent groups
more
how to avoid series effects in repeated measures?
counterbalance (start half with A, other half B)
what are repeated measures?
subjects, dose, time
transmitting expectations to experimenter/subjects
rosenthal effect
