correlation

• • Way to measure strength between two or more co-variables 
  • Plotted on scattergrams 
• • Correlations designed to investigate the strength and direction of relationship
  • Strength of the correlation is expressed by the correlation coefficient
• • Is always a figure between +1 and -1 ( +1 is a perfect positive and -1 is perfect negative)
• strength:

  • Able to look at the relationship between variables that you would not be able to experimental investigate - food and obesity
  • Correlations are useful as a tool of research as they provide a strength and direction of a relationship between variables and can be used as starting point to assess the relationship between variables 
  • Quick and economical
  • Use secondary data
• weakness:

  • Don't provide cause and effect 
  • Does not tell us why the variables are related 
  • Another untested variable is causing the relationship between co-variables → third variable problem