Correlations

• Positive correlation- relationship between two variables where they are related and change in the same direction
• Negative correlation- relationship between two variables where they change in the opposite direction
• Zero correlation- no relationship between the two variables, changing one has no effect on the other
• Correlation- illustrates the strength and direction of the association between two or more continuous variables
• Correlations are different to experiments because the independent variable isn't manipulated, so cause and effect can't be shown
• Linear correlations- systematic relationship between co-variables that is defined by a straight line
• Curvilinear correlations- non-linear relationship between variables, where the change between variables isn't constant
• Correlations are used in:

  • Naturalistic observation
  • Questionnaires
  • Secondary data
• Correlational co-efficient- statistical test to calculate how closely variables are associated

  A) negative

  B) positive

  C) weak

  D) strong

  E) -0.5

  F) +1.0

  G) zero

  
• Strengths of correlation:

  • Ethical- allows research into natural variables which would be otherwise impractical and unethical to manipulate
  • Cost-effective- good for preliminary research and handling secondary data
• Limitations of correlation:

  • Low internal validity- only shows relation between variables not causation between them
  • 3rd untested variable- might cause the correlation instead