statistical infrequency

• defining someone's behaviour according to how many times the behaviour is shown. so any common behaviour can be considered normal and therefore any uncommon can be considered abnormal.
• the majority of scores will cluster around the mean, the further we go above or below this the fewer people will attain this ‘score’. This is called a normal distribution.
• evaluation points (AO3)

  just because it's unusual doesn't mean it needs treatment - it is not sufficient as the sole basis for defining abnormality.

  some disorders are statistically very frequent - however they are still classified as 'abnormal'. Difficult to define what is statistically rare.