Normal Curve

(1) The familiar Normal Distribution "bell curve". The mathematical expression for the normal curve is y = (2?)-_e-x2/2. The normal curve is symmetric around the point x=0, and positive for every value of x. The area under the normal curve is unity, and the sd of the normal curve, suitably defined, is also unity.

(2) This bell-shaped curve is used to illustrate the shape of a normal distribution.