This is a gradual change in a characteristic across a population, it could be human height, mass and shoe size.
Continuous variation is represented as a histogram.
A histogram should show normal distribution, with most individuals around the average value and a few at the extremes.
The population can be clearly divided into discrete groups.
Individuals will fit into a group – there are no intermediates.
The ability to roll your tongue, blood group (A, B, AB, O) and hand dominance (left or right handed) are all examples.
Discontinuous variation is represented as a bar chart.