Experimental methods

• What is an aim in experimental methods?


  A statement developed from an initial theory that describes the purpose of the investigation
• What is a hypothesis?


  A clear, testable statement that states the relationship between variables to be investigated. There are two types.
• What is directional hypothesis/non-directional hypothesis?

  Directional = 'one-tailed' ; states clearly the difference between

  Non-directional = 'two-tailed' ; states the difference between the conditions but the nature of the difference isn't clear
• What is an experimental method

  Involves the manipulation of an independent variable to measure the effect on the dependent variable.

  The diff types of experiments may be laboratory, field, natural, quasi
• What are variables?

  Any thing that can vary/change within an investigation - they are used in experiments to determine if changes in one thing result in changes to another
• IV, DV, control

  Variable that is changed

  Variable that is measured

  Control - thing that stays the same
• What is operationalisation?

  Clearly defining variables in terms of how they can be measured e.g. "this juice will make them chattier" would become "this juice will make them have a higher word count in the next 5 mins than those who drink water"
• When do we use directional hypothesis?

  When findings of previous research studies suggest a particular outcome
• When do we use non-directional hypothesis?

  When there is no theory or previous research/findings from earlier studies are contradictory
• Writing a clear and testable hypothesis:

  • Clear and measurable IV and DV
  • Relationship between IV/DV is stated
  • Chosen directional/non-directional