Statistical Infrequency

Statistical infrequency

• Statistical infrequency (or statistical deviation as it is also known) defines abnormal behaviour using statistical measures

• A behaviour is regarded as abnormal if it is statistically uncommon/rare is that it is not present often or regularly per society, e.g.:

  • The average IQ is approximately 100

    • 95% of the population have an IQ which falls between 70 to 130

    • approximately 2.5% of the population have an IQ below 70

    • approximately 2.5% of the population have an IQ of 130+

  • About 1 in 300 (0.33%) people worldwide have schizophrenia, making it an abnormal condition/illness

• Rare behaviours/conditions are considered statistically abnormal for an example:

  • the case of HM who suffered extreme anterograde amnesia of a type which