Correlations

• What are correlations?

  • they investigate whether there is an association between the two variables
  • also reveal the strength of the association
  • unlike experiments, correlational studies do not tell us anything about causation/cause and effect relationships
• How to conduct correlational research

  • researcher measures the two variables of interest (e.g. aggression and stress) to obtain two sets of paired scores for each participant
  • there is no IV or DV - there are two co-variables
  • researcher then analyses the relationship between the two co-variables by: drawing a scatter graph and calculating a correlation coefficient
• Types of correlation

  • positive - as one variable increases so does the other
  • negative - as one variable increases, the other one decreases
  • zero - there is no relationship between the two co-variables
• Correlation coefficient

  • a statistical method for assessing the strength of a correlation
  • the sign (+ or -) indicates the direction of the correlation
  • the number (between 0 and 1) indicates the strength of the correlation/relationship between the two variables
• Scatter graphs

  • data is used analysing scatter graphs
  • plotted data shows you how 'strong', 'weak' or 'non-existent' the relationship is between the two variables
  • as there is no IV or DV it does not matter which variable is plotted on the X or Y axis
• Evaluations

  Strengths:

  • allows for predictions to be made - further experiments can be carried out if a correlation is found
  • researchers do not need to manipulate variables and therefore can use correlations in situations where it would be unethical to conduct an experiment

  Weaknesses:

  • don't allow us to see cause and effect relationship
  • may be extraneous variables impacting the relationship that aren't included in the study