Experimental method

• Aims

  General expression of what researcher intends to investigate
• operationalised

  clearly defined and measurable
• directional hypothesis

  states whether changes are greater/lesser - one tailed
• non-directional hypothesis

  just states that there is a difference/correlation/association - two tailed
• extraneous variables

  variables that make it more difficult to detect an effect
• confounding variable

  change systematically with the IV so we cannot be sure if change in DV is because of CV or IV
• Demand characteristics

  Any cue from the researcher/situation that may reveal aim of study and change pps behaviour
• investigator effects

  any effect of the investigators behaviour on the outcome of the research + on design decisions
• randomisation

  use of chance when designing an investigation to control bias
• standardisation

  using exactly the same formalised procedures for all participants in a research study - otherwise differences become EVs