correlations

• correlation


  a mathematical technique used to see whether two covariables are related
• correlations differ to experiments as:

  • the variables are measured, not manipulated
  • only an association is found, no cause & effect relationship
• covariables


  the variables investigated in a correlation
• correlation coefficients are calculated during correlational studies. This value determines the strength & relationship between two variables.
• negative correlation


  when one variable increases, the other decreases. The line of best fit has a negative gradient.
• positive correlation


  when one variable increases, the other also increases. The line of best fit has a positive gradient
• zero correlation


  no relationship is found between the covariables. No line of best fit as points on the scattergram are random
• curvilinear relationship


  as one variable increases, so does the other but only up to a certain point after which one variable continues to increase and the other begins to decrease. This forms an inverted U shape.
• A directional hypothesis for correlations states whether there will be a negative or positive correlation between the covariables
• a non-directional hypothesis for correlations states there will be a correlation but the type is unknown
• A strength of correlations is that secondary data can be used in the correlational study which makes it very quick to carry out
• A strength of correlations is that they are quick and economical to carry out
• A limitation of correlations is that it is difficult to establish a cause and effect relationship, only an association is found
• A limitation of correlational studies is that there may be a third variable presented. There may be a chance that there is another variable which the researcher is unaware of that is responsible for the relationship between the covariables