types of experimental design Flashcards
What is an experimental design?
How we allocate participants to the experimental groups.
in which type of experiments do we use experimental design?
Laboratory and field experiments.
explain the matched pairs design.
when researchers match the participants from the control and experimental group, for a particular participant variable.
ex: depression.
what are the pros of matched pairs design.
researchers have control over participant variables, so that it doesnt affect the experiment.
This is good, because it increases the internal validity of the experiment.
what are the cons of matched pairs design?
cant control every participant variable.
Time consuming, because researcher has to first identify personal characteristics that could affect the DV, and then identify participants with similar characteristics.
what is the indepenant group design?
when a researcher allocates different participants to control and experimental groups, without matching them.
what are the cons of independant grup design?
There may be participant variables that can affect the results, this decreases internal validity.
what should the researcher do when considering independant groups design?
Use random allocation, so that participant avriables are more likely to spread around.
what is repeated measures design?
when the same participants, take part in all the experimental conditions.
each participant takes part in each level of the IV.
what are the dissadvantages of repeated measures design?
- when participant is in both levels of the iv, he is more likely to figure out the aim of the experiment, thus leading to demand characteristics.
- Order effects.
what are order effects?
when the order of the experimental conditions influences the results of the study (In a repeated measures design).
what are the two ways order effects can happen?
- participants can get better at the task through practice.
- participants may get bored, and not try the same in the second trial.
What are the advantages of repeated measures design?
- No more participant variables that can act as confounding variables, which means higher internal validity.
- Need fewer particiopants to do number of tests.
what is the one slution to stop order effects? and explain it.
Counterbalancing.
When in a repeated measures design , different participants are made to take part in experimental conditions, in different orders.
describe what experimental designs can be used for quasi and natural experiments.
A repeatd measures design, might occur.
Although we dont have any control over the IV, we can still measure the personalities of the participants, and then match them, so matched pairing could work
Never independant group design, because is impossible to randomly allocate participants.
