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research methods: experimental methods - Coggle Diagram
research methods: experimental methods
Control of variables
Extraneous variables- the independent is manipulated to see how this effects the dependant variable
The only thing that should influence the IV is the DV, and any variables that interfere with the IV should be controlled or removed.
Confounding variables- the variable that influences both the IV and DV in a study, distorting the observed relationship between them.
experimental designs
independant groups
weakness: pps who occupy different conditions are not the same
pps are allocated to different groups where each group represents one experimental condition
strengths: order effects are not a problem and pps are also less likely to guess aim of the study
repeated measures
all pps take part in all conditions of the experiment
strengths: pps have to do at least two tasks in order and the order of these tasks may be significant - can overcome this with counterbalancing
weaknesses: order effects also arise bc repeating two tasks could create boredom or fatigue that might cause deterioration in performance on the second task, so it matters in what order you complete the tasks
matched pairs
pairs of participants are first matched on some variable(s) that may affect the DV, then one member of each pair is assigned to condition A and the other to condition B.
strengths: order effects and demand characteristics are less of a problem because only one person does one condition in each pair
weakness: participants can never be matched exactly
Hypotheses
Definition- a statement made at the start of a study that clearly states the relationship between variables as stated by the theory.
Directional hypothesis- when the researcher makes clear the sort of difference that is anticipated between two conditions/groups of people
Non-directional hypothesis- when a difference is stated between two conditions/groups of people, but the nature of the difference isn't specified