variables and hypotheses

independent variable

the variable the psychologist manipulates

dependent variable

variable which is measured by the psychologist

operationalisation

giving a precise definition of the behaviour being measured/manipulated

aim

a broad statement of the purpose of the research

experimental/ alternate hypothesis

predicts something will happen (IV will not affect the DV)

extraneous variable

variables that are not being measured or manipulated but affect all of participants behaviour equally

confounding variable

variables that are not being measured or manipulated that affect some participants behaviour

null hypothesis

doesn't predict a change or difference (IV will not affect the DV)

directional hypothesis

hypothesis that suggests there will be a relationship between variables

- IV will affect DV in one specific outcome

non-directional hypothesis

hypothesis that suggests there will be a relationship between variables

- IV will affect DV with no specific outcome

null

there will be no significant difference

alternate directional

there will be an increase/ decrease

alternate non-directional

there will be a difference

standardisation

keeping all variables and procedures consistent so that each participants experiences the same conditions

control group

group in an experiment used as a baseline that does not receive the treatment or independent variable

it is used to compare to the experimental group