Experimental Method

• Aims - developed from theories and are general statements that describe the purpose of an investigation
• Hypothesis - a testable statement which predicts the outcome at the start of a study
• Directional hypothesis - identifies the direction of difference between the two conditions (e.g. A will be more than B)
• Non-directional hypothesis - states a difference between conditions but the nature of the difference is not made clear (there will be a difference between A and B)
• Null hypothesis - a statement of no difference (there will be no difference in A and B)
• Non-directional hypothesis is used when there is no previous research/where the previous research is contradictory
• IV - the variable that is changed/manipulated by the experimenter
• DV - the variable that is measured by the experimenter
• Levels of IV - there are usually 2 levels:

  • experimental condition
  • control condition
• Operationalisation - variables being investigated should be clearly defined and measurable