correlations

• a correlation looks at the relationship between 2 variables and shows the strength of the relationship
• a positive correlation is when 1 variable increases the other variable increases too
• a negative correlation is when 1 variable increases the other variable decreases
• the correlation co - efficient is a value/number that tells us the strength of the correlation between two variables
• perfect correlation = 1

  strong correlation = 0.7, 0.8, 0.9

  moderate correlation = 0.4, 0.5, 0.6

  weak correlation = 0.1, 0.2, 0.3

  no correlation = 0
• experiments vs correlations

  • experiments look for differences whereas correlations look for relationships
  • experiments establish cause and effect however correlations don't
  • experiments have a high degree of control and rely on the idea of one variable changing caused the difference whereas a correlation has no control it looks for relationships between variables
• strengths of correlations - useful when its unethical to do an experiment, allows predictions, is quick and economical and can be used as a starting point for further research
• weaknesses of correlations - can't show causation (cause of correlation), often can be misinterpreted as people think that one must cause the other and studies only tell us if variables are related and not why