Therefore, distances are often normalized by dividing the distance for each variable by the range of that
attribute, so that the distance for each input variable is in the range 0..1. However, this allows outliers
(extreme values) to have a profound effect on the contribution of an attribute. For example, if a variable has
values which are in the range 0..10 in almost every case but with one (possibly erroneous) value of 50, then
dividing by the range would almost always result in a value less than 0.2. A more robust alternative is to
divide the values by the standard deviation in order to reduce the effect of extreme values on the typical cases.