evaluate the statistical infrequency definition:
+ its reliable and objective because its based on mathematical statistics
+ its a straightforward deinition
- it ignores how abnormal traits that lie outside the average may be desireable e.g. extreme intelligence
- definition is arbitrary
- not all abnormal behaviours are infrequent
- cultural relativsm - certain behaviours are normal in some cultures that are abnormal in others e.g. eating with our hands