Investigation Design

• Empirical Method


  Use of methods that rely of direct sensory experience
• Objectivity

  Universal agreement
• Random Allocation


  Everyone gets an equal chance to be in groups/conditions (unbiased)
• Standardising


  Everyone needs to experience the same conditions/ things in an experiment (this allows you to make comparisons).
• Operationalising


  Defining the 'fuzzy concepts' (variables) into things we can see and count.
• Control


  Cause and effect- what you have manipulated caused something to happen
• Extraneous variables(caterpillars)


  Anything that could impact one of the two conditions, or impacts a few people in the condition but not everyone.
• When do EVs happen?


  When things aren't kept the same.
• Controls(boot)


  Materials

  Understanding

  Location

  Time

  Investigation

  (Must stay the same, constant and be fair)
• Confounding variables (butterflies)

  Uncontrolled extraneous variable which has impacted the study
• What is an aim?

  Why a study is taking place or why a topic is being studied
• How do you write an aim?

  • What the study is (difference/correlation)
  • What is being studied (IV)
  • What you want to achieve (DV)
• What is a hypothesis?

  Prediction based around an aim
• Experimental Hypothesis

  Any difference is beyond chance, IV is causing a difference

  Can be proved
• Null Hypothesis

  • Difference is happening by chance (this is what you aim to support)
  • Cannot be proved
• Directional Hypothesis:

  • One condition will 'beat' the other.
  • C1 → Change word → DV → C2 (eg boys/will run faster/over 100m/than girls)
  • Needs previous research
• Non-directional Hypothesis:

  • Conditions will be different but we don't know which
  • Difference → DV → C1 → C2 (eg there will be a difference/ in the time taken in running 100m/ between boys/ and girls)
• External Validity

  Concerned with how much the findings can be generalised to settings beyond the study.
• Population validity

  The extent to which findings from the study can be generalised to other groups of people. This is affected by an unrepresentative sample.

  (High population validity: findings can be generalised to others.)
• Ecological validity

  The extent to which research findings can be generalised to real life situations. This is affected by an unrealistic setting.
• Internal validity

  Refers to the extent to which we can be sure the findings of a study are due to what we say they are.
• Demand characteristics

  When participants work out the hypothesis of a study and act accordingly.
• Investigator effects

  Researcher impacts the findings- knowingly or not- hey keep things constant.
• Single blind

  Participant doesn't know if they are in a treatment group or control (placebo) group. Researcher knows.
• Double blind

  Neither the researcher or participants know who is treatment and who is control.
• Reliability

  This refers to consistency- same outcome every time.
• The better the control over the variables= higher the reliability due to increased cause and effect.
• Pilot studies

  'Dress rehearsal' that is designed to find extraneous variables.

  These are not about the findings, to see if it's worth it or to make a massive change.