research methods Flashcards
aim
a general expression of what the researcher intends to investigate.
independent variable
the aspect of the experiment that the researcher changes or manipulates.
dependent variables
the data that the researcher measures
extraneous variables
a variable other than the IV that may affect the DV and should therefore be controlled.
hypothesis
a prediction or a testable statement about what the researcher thinks will happen.
null hypothesis
predicts there will be no difference between the groups.
alternative hypothesis
predicts a difference or a relationship between groups/ conditions.
(alternative) directional hypothesis
predicts a difference/ relationship between groups/ conditions and states the direction of the difference.
(alternative) non-directional hypothesis
predicts a difference/relationship between groups but does not state the direction of the difference.
lab experiment
artificial experiment
controlled/standardised procedure
researcher manipulates IV i measure the effect of the DV
p’s know they are in a study
field experiment
IV is manipulated.
carried out in a natural environment.
p’s don’t know they are in an experiment.
natural experiment
in a natural environment.
IV is naturally occurring (eg natural disaster).
quasi experiment
in either lab or natural environment.
IV is something that naturally occurs within a person (characteristic).
cannot randomly allocate p’s to conditions.
internal validity
how much the IV affects the DV alone and caused a changed
mundane realism
the extent to which the TASK is representative of that behaviour in the real world.
ecological validity
the extent that the results can be generalised to another setting
demand characteristics
cues in the environment that may reveal the aim of the experiment causing participants to change behaviour.
experimental designs
refers to how participants are organised across the conditions
independent groups
each participant takes part in one condition only
repeated measures
each participant takes part in both conditions
matched pairs
each participant only takes part in one condition only, but participants are matched on variables considered relevant (age, gender,IQ)
experimental realism
whether an experiment has a psychological impact and “feels real” to participants.
confounding variables
variables apart from the IV that have affected the DV
uncontrolled variables
variables that cannot be controlled for. eg participants mood
situational confounding variables
features of the experimental situation
participant confounding variables
are do to with differences between participants
other types of extraneous variables
researcher bias, demand characteristics, order effect.
investigator effects
where a researcher acts in a way to support their prediction. this can be particular problem when observing events that can be interpreted in more than one way.
random allocation
each person has an equal chance of being put into either condition
standardised procedure
the process in which procedures used in research are kept the same, allows for replication to determine reliability.
randomisation
presenting any stimuli in an experiment in a “random manner” to avoid it having an effect on the DV, prevents order effects and situational extraneous variables.
single blind test
participants don’t know which condition of a study they are in, prevents demand characteristics.
double blind test
neither participants nor investigators know which condition the participants are in, prevents researcher bias.
target population
the group of people the researcher wants to study.
a sample
a small group of people who represents the target population and who is studied.
random sampling, how is it done?
where every member of the target population has an equal chance of being chosen.
how:
1. need a sampling frame, a complete list of all members of the target population is obtained.
2.all the names are assigned a number.
3.sample is selected randomly.
opportunity sampling, how is it done?
recruiting anyone who happens to be available at the time of your study.
how:
•researcher goes somewhere they are likely to find their target population and ask people to take part.
volunteer sampling, how is it done?
when people actively volunteer to be in a study by responding to a request which has been advertised by the researcher.
how:
p’s self select by responding to an advert
systematic sampling, how is it done?
involves selecting names from the sampling frame at regular intervals.
how:
1. list of people in the target population organised.
2. a sampling system is nominated.
3. researcher then works through the sampling frame until the samples complete.
stratified sampling, how is it done?
participants are selected from different subgroups in the target population in proportion to the subgroups frequency in the population.
reliability
refers to the extent to which something is consistent.
test-retest reliability
measures test consistency; the reliability of a test measured over time.
inter-rarer reliability
the degree of agreement among raters.
validity
refers to the extent to which something is measuring what it is claiming to measure.
external validity
refers to the extent the results can be generalised to other settings.
population validity
describes how well the sample can be generalised to a POPULATION as a whole.
temporal validity
refers to whether the findings are still valid TODAY.
lab experiment advantages
•can control extraneous variables increasing internal validity.
•standardised procedure so replication can be done to see if the findings are reliable.
lab experiment disadvantages
•low ecological validity.
•lack mundane realism.
•p’s knowing they are being tested could cause demand characteristics.
field experiment advantages
•environment is natural so higher ecological validity.
•p’s don’t know they are being tested reducing demand characteristics.
field experiment disadvantages
•less control of extraneous variables decreasing internal validity.
•ethical issues if p’s are unaware they are in an experiment.
natural experiment advantages
•provides opportunities that might not otherwise be available.
•high ecological validity as it’s a real-life event.
natural experiment disadvantages
•difficult to establish the cause.
•event may happen very quickly.
•p’s may not be randomly allocated.
quasi experiment advantages
•carried out in often controlled conditions
quasi experiment disadvantages
•p’s cannot be randomly allocated resulting in participant confounding variables.
independent groups strengths
• reduced demand characteristics.
•minimises order effects. eg no practise/fatigued
independent groups weaknesses
•participant extraneous variables
•less economical/ time consuming as you need more p’s
repeated measures strengths
•participant extraneous variables are controlled for
•less p’s needed so less time consuming/expensive
repeated measures weaknesses
•order effects
•demand characteristics
matched pairs strengths
•order effects and demand characteristics
•participant extraneous variables are reduced
matched pairs weaknesses
•the p’s cannot be truly matched.
•time consuming and expensive.
matched pairs weaknesses
•the p’s cannot be truly matched.
•time consuming and expensive.
random sampling advantage
lack of researcher bias
disadvantages of random sampling
•impractical (time and effort).
•not completely representative.
advantages of opportunity sampling
•simple and easy to conduct.
•field/natural experiments must use those available.
disadvantages of opportunity sampling
•unrepresentative.
•researcher bias.
advantages of volunteer sampling
•most convenient.
•reach a wider audience.
disadvantages of volunteer sampling
•biased sample
eg particular interest, altruistic
advantages of systematic sampling
•no researcher bias.
•simple (with sampling frame).