one of the most obvious ways to define anything as ‘normal’ or ‘abnormal is according to the number of times we observe it
statistics refer to numbers; when something frequently occurs, it can be considered normal and when it does not frequently occur, it can be seen as abnormal
in this definition of abnormality behaviours which are seen as statistically rare are said to be abnormal
an example of statistical infrequency is IQ as about 95% of adults in the UK have an IQ between 70 and 130
