aim
a general statement of what the researcher intends to investigate (the purpose of the study)
hypothesis
a statement that states the predicted outcome of the study
directional (one-tailed) hypothesis
a prediction that states the direction the results will go in (eg: noise will negatively affect concentration)
non directional (two-tailed) hypothesis
a prediction that does not state the direction the results will go in (eg: noise will affect concentration)
null hypothesis
a prediction that suggests there is no relationship between measured variables (eg: noise does not affect concentration)
operationalisation
clearly defining variables in terms of how they can be measured (eg: speed - 10mph and 60mph)
independent variable (IV)
an aspect of the experimental situation that is changed
dependent variable (DV)
what is measured by the experimenter caused by the change in IV
extraneous variable (EV)
any other variable than the IV that may affect the DV if not controlled
confounding variable (CV)
influences both the IV and the DV making it hard to determine the true cause and effect relationship
demand characteristics
any cue from the researcher/situation that may reveal the true purpose of the study changing the participants behaviour
investigator effects
any effect from the investigator’s behaviour on the research outcome
how to minimise EVs/CVs effects?
independent group design
participants are placed in separate groups/conditions
strengths of independent group design
weaknesses of independent group design
repeated measures design
all participants experience both conditions
strengths of repeated measures design
weaknesses of repeated measures design
matched pair design
two groups of participants are matched up on key/similar characteristics
strengths of matched pair design
weaknesses of matched pair design
laboratory experiment
an experiment that takes place in a controlled environment
strengths of laboratory experiment