Situational variable
variables present in the environment that might effect the results of the experiment. e.g temperature,noise,light levels
Participant variable
when a participants mood,ability,nationality,etc. might effect the results
order effects
when the particpants worsen or improve in the second condition because they became tired or have parcticed.
standardised procedure
all parts of the procedure are kept the same. So every participant experiences the same condition
investigator effects
when the researcher unintentionally gives away the aims of the investigation
demand characteristics
when the participants alter their behavior because they discovered the aims of the study.
counterbalncing
half of the participants experience condition A then B whilst the other half experience condition B then A. So that order effects cancel out.
Random allocation or randomisation
participants are randomly assigned to a condition
single blind technique
the true aims of the investigation are kept hidden from the participants
double blind technique
when the aims of the investigation is kept from both the investigators and the participants.
Questionnaires
Pre-written questions handed to participants which allow them to directly provide information about themselves. ADVANTAGES: highly replicable,time and cost efficient, investigator effects reduced(investigator not present)DISADVANTAGES : people may modify answers to show them selves in best light, participant samples biased, participants unable to ask for help
interviews
allow participants to directly provide information about themselves.Pre-written set of questions. all participants asked the same questions.ADVANTAGES: more appropriate when dealing with sensitive or complex issues, misunderstandings may be followed up immediately. DISADVANTAGES:Participants modify answers to bring themsleves into light, interviewer effects(low inter rater reliability), time consuming.
Field experiment
same as laboratory experiment but in a real life setting.ADVANTAGES-Participants may act more naturally than in laboratory,demand characteristics reduced(participants unaware they are taking part),determine cause and effect in most situations.DISADVANTAGES-researchers control over enviroment reduces validity,partcipants if unaware they are taking part may become distressed by manipulation of independent variablr,population validity reduced(reasercher no control over participants)
Laboratory experiment
Take place in laboratory in a university. Directly manipulated by researcher.ADVANTAGES-cause and effect can be inferred with reasonable confidence,easy to replicate,specialist equipemnt can be used to deepen understanding.DISADVANTAGES-participants may not demonstrate real life behavior,demand characteristicts, ethical rules limit researchers
Natural experiment
Reasercher does not manipulate independent variable(it is naturally occuring).ADVANTAGES-can study unethical or impractical studies if studied in a different way,researcher able to study real problems and situations,demand characteristics reduced.DISADVANTAGES-reasercher has no control over enviroment,ethical guidelines of consent may not be met,often impossible to repicate
correlations
Relation ship between two variables.ADVANTAGES-use pre-existing data(time and cost effective)Study impractical or unethical studies if studied in different way,precise method(tell researchers exact strength)DISADVANTAGES-impossible to establish cause and effect, inaccurate conclusions may infer something else,only measure linear relationships(clear)
case study
In depth study of a single person and focus on one aspect of their behaviour.ADVANTAGES-allow to study impractical studies,suggest new hypothesis for existing studies,complex interactions can be studiedDISADVANTAGES-hard to generalise results,ethical issues,interpretation of researcher might be different or biased to what is actually happening
observation
behaviour is watched and recorded. Structured observation- decide what they record. ADVANTAGES-participants act naturally,allow researchers to study impractical or unethical studies if studied in different way,investigating new areas help produce hypothesis. DISADVANTAGES-If participants know they’re observed they can alter behavior,ethical issues(participants dont know they are being observed),Low reliability(observers dissagree on judgment)
Random sampling
picked out of a hat. ADVANTAGES-not a biased sample,cost and time effective, equal chance.DISADVANTAGES-target population may not be represented,participnats may not want to take part.
opportunity sampling
using participants that are ready to use.ADVANTAGES- ethical,time and cost efffective.DISADVANTAGES-biased sample not all of target population is represented,not an equal opprotunity.
stratified sampling
identifies sub groups of population.ADVANTAGES-all of target population represented,most reliable results. DISADVANTAGES- time consuming,people can refuse, invalid conclusions
self selected (volunteer) sampling
asking participants to take part.ADVANTAGES-most ethical,minimal effort,possible to recruit target populationDISADVANTAGES-target population may not be represnented
Repeated measures
Participant experience all conditions.fewer people needed. order effect affect results. Participnat characteristics(extraneous variable) kept constant
Independant measures
Each group experiences only one condition. Participant characteristics may affect results. More participants are needed
Matched pairs
two groups of participants are matched on key characteristics. Time consuming.Not possible to match all characteristics.More participants are needed.
experimental designs definition
three different ways of deciding which participants are in which condition.
Independent measures
repeated measures
Matched psirs
reliability
when something can be repeated multiple times and you get the same result.( consistency of an outcome)
internal validity(validity)
how confident are we that the test measures what it intends to.
ecological validity
how generalisable the findings are to the real world.(situations or setting typical of everyday life.)
population validity
how generalisable the findings are to a larger group of people(target population)
Protection from harm
Participants should be no worse off when they leave an experiment as to when they arrived.
informed consent
letting participants know what they are going to have to do in the study so their consent is 100% valid
deception
Participants should know all the information about the experiment. Only if something might affect the results some things can be kept a secret
right to withdraw
participants are able to withdraw at any moment even after the experiment finished
debrief
if consent cannot be obtained participants must be fully debriefed afterwards. The participants have the right to withdraw their information
Qualitative data
mainly in words
Quantitive data
numerical
primary data
direct for a specific research
secondary data
already been collected
Bar chart
data in categories
histogram
groups numbers into ranges
scatter graphs
used for correlation data to show relation ship.
independent variable
the variable the researcher manipulates
x-axis
dependent variable
the variable the researcher measures
y-axis
confounding variable
when a extraneous variable isn’t controlled and impacts dependent variable
Null vs Alternative hypothesis
Null: a hypothesis that predicts no significant difference or correlation in the results of a study.
Alternative hypothesis : a testable statement that predicts a significant difference or correlation.
non directional- there will be a difference but doesn’t suggest direction e.g a gender difference
directional- states the direction of the difference or correlation. e.g males higher than female