Normal Distribution

A standard normal distribution, on the other hand, is one for which the area of the normal curve is equal to unity(1). As such, this distribution is also, otherwise known as the unit normal distribution, and the curve produced thereby is called the Standard Probability curve. Any distribution, not withstanding the values of its n, m, or  can be converted into a standard normal distribution.

Measurement of areas of a Standard Normal Curve

For measuring the different areas of a standard normal curve. Where m = 0, and  σ = 1, first we are to change the values of X into the values of Z by the model, Z = x-m/σ and then to find out from the Area Table of a Normal curve, the area enclosed by the various values of Z.