research methods: experiments Flashcards
(27 cards)
what is an aim
general statement of what the researcher intends to investigate, the purpose
what is a hypothesis
specific, testable statement in which the researcher predicts the outcome between the variables
what is a directional hypothesis
one tailed
predicts the direction they think the results will go in
previous research is conducted to show the difference between co-variables
what is a non directional hypothesis
two tailed
does not predict the direction that they think the results will go in
no previous research
what is a lab experiment
conducted in a highly controlled environment where the researcher manipulated the IV to measure the effect on the DV
lab experiment AO3
high control on extraneous variables
high in reliability
lacks ecological validity
prone to demand characteristics
field experiment
takes place in a natural environment eg school
where the researcher manipulates the IV and measures the effect on the DV
field experiment AO3
less prone to demand characteristics
high ecological validity
low in reliability
ethical issues
natural experiment
researcher takes advantage of naturally occurring IV
natural experiment AO3
high ecological validity
provide opportunities for research that may not be undertaken due to ethical reasons
low control over extraneous variables
naturally occurring events are rare, limits opportunities for research
quasi experiment
an experiment which has an IV based on an existing individual differences between people, which the researcher has not manipulated eg age or gender and researcher measures effect on DV
quasi experiment AO3
sample bias as they have unique characteristics, difficult to generalise to target population, decreasing external validity
independent groups design
ppts take part in one condition, each condition has different group of ppts
- a group of ppts are recruited
- split into equal sized groups
- different group allocated different conditions
independent groups design AO3
no order effects as ppts take part in one condition
individual differences may affect the DV, lowering internal validity
more ppts are required as 2 different group conditions
repeated measures design
all ppts take part in both conditions of the experiment
-ppts complete one condition
-after a time delay (one hour) they will complete the other condition
- DV should be different but task difficulty/ measuring same thing should be the same
repeated measures AO3
no individual differences
requires fewer ppts
order effects may occur, may perform worse in 2nd condition due to eg boredom, fatigue, lowering internal validity
prone to demand characteristics
matched pairs design
ppts are matched on important characteristics in the study eg age or IQ
-choose a variable to match ppts on
- test the ppt on this variable before the study
- match ppts with same scores
-randomly allocate each member of pair to condition
what is a pilot study
small scale trail run of research before the real main scale research
takes place to identify any problems and amend them
what are the aims of a pilot study
- check standardised procedures and general design
-check the amount of time given to ppts is enough to complete task - make sure questions are clear
- for observations check behaviour categories are understood
-extraneous variables can be identified and possibly eliminated
-ask ppts to discuss their experiences of the experiment
counterbalancing
WHY
-to control and reduce order effects
HOW
-half the ppts complete condition A then condition B
-the other half complete condition B first then condition A
-order effects are balanced distributed across both conditions
random allocation
WHY
-ensures that each ppt has the same chance of being in one condition as any other condition
HOW
-write the names of the ppts on equal sized pieces of paper
-put paper in a hat
-then randomly pick out ppts names and place half in condition 1 and the other half in condition 2
what is internal validity
is the research measuring what it intends to measure
what is external validity
whether the findings can be generalised outside of the study
what is ecological validity
a form of external validity, the extent to which findings can be generalised beyond the setting of the study to real life settings