Statistical normality

What it is "normal?"

Science statistics is a function of density, that is, to plot (plot the data on the XY axes), these data are grouped in a central area called normality.
The curve that produces the graph is symmetric and called "Gauss curve or Bell.
Normal in humans is based on a concept statistical approach that is generated by a series of values, such as: Weight, glucose, blood pressure, cholesterol, etc. 
Search discriminating characteristics between healthy people and sick people.