Java实现Excel中的NORMSDIST函数和NORMSINV函数

<dependency>
   <groupId>org.apache.commons</groupId>
   <artifactId>commons-math3</artifactId>
   <version>3.6.1</version>
</dependency>

/**
     * 标准正态分布累积概率分布函数 NORMSDIST 实现一
     *
     * @param a
     * @return double
     * @author WH
     * @date 2013/08/23 16:38
     */
    public static double normsdist(double a) {
        double p = 0.2316419;
        double b1 = 0.31938153;
        double b2 = -0.356563782;
        double b3 = 1.781477937;
        double b4 = -1.821255978;
        double b5 = 1.330274429;
        double x = Math.abs(a);
        double t = 1 / (1 + p * x);
        double val = 1 - (1 / (Math.sqrt(2 * Math.PI)) * Math.exp(-1 * Math.pow(a, 2) / 2)) * (b1 * t + b2 * Math.pow(t, 2) + b3 * Math.pow(t,