APPROXIMATION TO THE CUMULATIVE NORMAL DISTRIBUTION USING HYPERBOLIC TANGENT BASED FUNCTIONS

This paper presents a method for approximation of the stan- dard normal distribution by using hyperbolic tangent based functions. The presented approximate formula for the cumulative distribution de- pends on one numerical coecient only, and its accuracy is admissible. Furthermore, in some particular cases, closed forms of inverse formulas are derived. Numerical results of the present method are compared with those of an existing method.