ANATOMY OF THE STANDARD NORMAL CURVE The Standard Normal Curve is a normal probability distribution with the following characteristics: Parameters: m = 0 and s = 1. The total area under the curve is equal to 1. The curve extends indefinitely in both directions along the horizontal axis. Symmetric about its mean of 0. Most of the area under the curve is between -3 and 3. The Standard Normal Curve is used as the basis for determining the area under the curve for all normal probability distributions. Non-Standard Normal probability distributions have means and standard deviations other than 0 and 1, respectively. The values for these distributions are transformed to the Standard Normal via use of the z-score formula below. Once transformed, areas under the curve may be calculated. z -3 -2 -1 1 2 3