Psychology

• strengths of correlations 


  • good starting point for research - if two variables are related it gives researcher ideas for further investigations
  • can be used to investigate complex relationships - correlation has many uses
• weaknesses of correlations


  • cannot infer cause and effect relationships from correlations - limits usefulness of technique
  • an unknown , untested third variable can influence the relationship between the original co - variables - means its possible to draw wrong conclusions
• bar chart


  used when data is divided into categories
• histograms


  when data is continuous and shown by the bars touching each other
• scattergrams 


  doesn't show a difference but correlations between two co-variables
• normal distribution 


  • forms a bell shaped curve
  • mean , mode and median are all in the exact midpoint
• positive distribution 


  long tail is on the positive (right) side of the peak and most of the distribution is on the left
• Negative distribution 


  • long tail is on the negative (left) side and most of the distribution is on the right