correlations

• what is a correlation

  a mathematical technique in which a researcher investigates an association between two variables called co-variables.
• what are the three types of correlations

  positive

  negative

  zero
• what is a positive correlation


  as one co-variable increases, so does the other
• what is a negative correlation


  as one co-variable increases the other decreases.
• what is zero correlation

  when there is no relationship between the co-variables.
• what is the difference between correlations and experiments?


  experiment: the researcher controls or manipulates the independent variable in order to measure the effect on the dependant variable.

  correlation: no such manipulation of one variable therefore it is not possible to establish the cause and effect between variables.
• strengths of correlations


  • provide precise and quantifiable measures of how two variables are related.
  • may suggest ideas for future research if variables are strongly related or show a pattern.
  • quick and economical to carry out.
  • no need for a controlled environment and no manipulation of variables is required.
  • data can be collected by others e.g governmental statistics, therefore are less time-consuming.
• limitations of correlations


  • can only tell us how variables are related not why.
  • occasionally can be misused or misinterpreted.
  • we do not know which co-variable is causing the other to change.