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~psychology~ RESEARCH METHODS (control variables (how to minimise…
~psychology~
RESEARCH METHODS
experimental methods
variables in an experiment
the variables that the researcher is going to be changing and the effect of the change
any effect on the dv should be caused by the changed in the iv
-independent variables-
the part of the experiment that is manipulated by the researcher, or changes naturally
needs to be a control condition to be able to compare
-dependent variables-
the variable that is measured by the researcher
operationalisation
clearly defining variables so they can be easily measured
hypotheses
a testable statement made at the start of the study that sets out the relationship between the variables that will be investigated
-directional hypothesis (one tailed)-
the researcher makes it clear what sort of difference or relationship may be seen e.g/ 'there will be more'
-non directional hypothesis (two tailed)-
the direction of the outcome isn't mentioned e.g/ 'there will be a difference'
aims
a general statement of what the researcher intends to investigate
types of experiments
natural experiments
when the researcher takes advantage of a pre-existing iv
-evaluation of natural experiments-
+provides opportunities for research that might not be practical or ethical otherwise
+have high external validity because its a real life setting
-hard to generalise, a natural event could also effect it
field experiments
the iv is manipulated in an everyday setting
-evaluation of field experiments-
+they have higher mundane realise because of the real life setting
+behaviour is more authentic
-less control over extraneous variables
-it is hard to replicate
-can be time consuming and costly
-if the patients are unaware there could be possible ethical issues
lab experiments
conducted in highly controlled environments where the researcher manipulates the iv and records the dv
-evaluation of lab experiments-
+high control over extraneous variables
+replication is easy due to the high control levels
-participants are aware they're being tested so there could be a possibility of demand characteristics
-it is artificial so may not be able to be generalised
-low mundane realism which may not represent real life
quasi experiments
the iv is an existing difference between people e.g/ gender or age
-evaluation of quasi experiments*
+carried out under controlled conditions
+high control over extraneous variables
+replication is easy due to the high control levels
-participants are aware they're being tested so there could be demand characteristics
-participants cant be randomly allocated so there may be confounding variables
control variables
investigator effects
any behaviour that the investigator does that effects the dv
e.g/ selection of the participants or how the experiment is carried out
demand characteristics
when participants are aware of what is going on in the experiment so change their behaviour to go for the experiment or go against the experiment
confounding variables
variables that change with the iv and can change the dv so it is unsure what actually effected the dv
how to minimise extraneous or confounding variables
randomisation
having things randomly generated
standardisation
using the exact same procedure for all participants
extraneous variables
a variable that may effect the dv, that is not the iv, if it isn't controlled
e.g/ age of participants, lighting or sounds
reliability and validity
reliability
refers to the consistency of the results
-internal reliability-
the extent to which something is consistent with in itself
-e.g/ when measuring aggression it need to be sure that all the behavioural categories are measuring aggression reliably
-external reliability-
the extent to the consistency through out time
-e.g/ if someone got something on an iq they should get the same in like 8 months for it to be reliable
validity
how accurate the results are, making sure we are measuring what we intended to measure
-internal validity-
whether the results are effected by confounding variables
-external validity-
the extent to which the results can be generalised
ecological validity
-whether the results can be generalised to other settings
temporal validity
-whether the results can be generalised from the time the experiment was done
population validity
-whether the results can be generalised to other groups of people
non experimental methods
questionnaires
pre set list of questions to which the participants respond with written answers
open questions
the respondent can answer how they want, this will produce qualitative data
-evaluation of open questions-
+can expand their so more detail is collected
+can gain a new insight with possible unexpected answers
-it can be more difficult to draw conclusions
closed questions
the respondent has a fixed range of responses, this produces quantitative data
-evaluation of closed questions-
+easy to draw conclusions
-being forced to select answers may not represent the respondents true thoughts so can lack validity
evaluation of questionnaires
+cost effective
+can gather large amounts of data quickly
+can also be done with out the researcher being present
-social desirability may mean respondents don't answer the questions truthfully
-responder bias may effect results e.g/ always answering yes
designing a questionnaire
-bias-
-questions that don't lead respondents to give a particular answer
-assumptions-
-avoids making assumptions about the respondent
-clarity-
-clear questions that are easy to understand
-non intrusive-
-avoids questions that are too personal
-checked-
-questionnaire is piloted to make sure the questions are understood and interpreted correctly
observations
where the researcher watches the experiment happen
observational methods
-overt observations-
-participants are aware they're being observed
-covert observations-
-totally unaware they are the focus of the study
-controlled-
-environment provided by researcher
-participant observations-
-when the observer secretly becomes part of the group they're observing
-naturalistic-
-takes place in the participants natural environment
-non participant observation-
-where the observer is separate to the group being observed
interviews
they're a self report method that collects qualitative data but can collect quantitative data
unstructured interviews
there are no set questions but there is an aim that a certain topic will be discussed, participants are encouraged to expand on their answers
-evaluation of unstructured interviews-
+much more flexible which allows for more insight
-trying to analyse data is very difficult
semi structured interviews
usually a list of questions but interviews can follow up on answers
structured interviews
made up of pre determined questions that are asked in a fixed order
-evaluation of structured interviews-
+easy to replicate
-difficult for interviewers to deviate from the topic and allow participants to expand their answers
designing an interview
-recording-
-may take notes or record the answers to the questions
-ethical issues-
-participants should be reminded their answers will be treated confidentially
-an interview schedule-
-standardised questions the interviewer intends to ask
-effect of interviewer-
-a strength is that if the interviewer seems interested the participant may be willing to give more information
-they can do this by being careful with their non-verbal communication
experimental designs
the way groups are assigned
repeated groups
where all participants take part in both conditions
-evaluation of repeated groups-
+avoids participant variables
+requires fewer participants
-order effects are likely to occur
-counterbalancing is used to avoid this where the group is split in to two, one group will do condition a then condition b and the other group will to b then a
matched pairs
where pairs are matched by a specific variable and then there's one of the pair in each group
-evaluation of matched pairs-
+the issue of participant variables is reduced
+order effects are avoided
-can't match people completely
-very time consuming
independent groups
two different groups of participants experience two different conditions
-evaluation of independent groups-
+order effects are avoided (when the participant becomes aware of or bored of a experiment procedure)
-participant variables may effect results
-more participants are needed