Experimental Methods

• Aim

  • A general statement of what the researcher intends to investigate and the purpose of the study. Aims are generated from a theory
• Hypothesis

  • A clear, precise and testable statement that states the relationship between the variables to be invested as stated by the theory
• A hypothesis could be:

  • Directional (one-tailed) - states the direction of the difference or relationship. E.g. drinking water improves exam performance
  • Non-directional (two-tailed) - does not state the direction. E.g. drinking water affects exam performance
• Independent Variable (IV)

  • Some aspect of the experimental situation that is manipulated by the researcher -or changes naturally- so the effect on the dependant variable (DV) can be measured
• Dependant Variable

  • The variable that is measured by the researcher. Any change in the DV should be cause by the IV
• Extraneous Variable

  • Factors other than the independent and dependant variables that may unintentionally influence the results of an experiment. E.g. Time of day
• Confound Variables

  • Effects of the extraneous variables