2. Convert the Z-score to a cumulative probability: The cumulative probability associated with a Z-score allows you to determine the percentage of the total area under the standard normal curve that ...

John P. Mills, Table of the Ratio: Area to Bounding Ordinate, for Any Portion of Normal Curve, Biometrika, Vol. 18, No. 3/4 (Nov., 1926), pp. 395-400 ...