deviation from mean

• 1. Statistical infrequency

  Behaviours that deviate from the mean are abnormal and the further from the mean the more abnormal the behaviour. 

  This implies there is a normal curve for behaviours. 
• Strengths of statistical infrequency

  • Objective approach – once a ‘cut off’ point has been decided for all behaviour – it avoids bias as to what is abnormal. 
  • Evidence – to justify a request for treatment or to gain psychiatric help using quantitative data. 
• Weaknesses of statistical infrequency

  • Not all abnormal behaviours are undesirable and not all normal behaviours are desirable. 
  • Cultural bias – different ideas of abnormality in different cultures e.g. women driving/abortion