public double getAsDouble()

in commons-statistics-descriptive/src/main/java/org/apache/commons/statistics/descriptive/Kurtosis.java [249:276]

• 23 lines of code
• 7 McCabe index (conditional complexity)

    public double getAsDouble() {
        // This method checks the sum of squared or fourth deviations is finite
        // to provide a consistent NaN when the computation is not possible.

        if (sq.n < (biased ? LENGTH_TWO : LENGTH_FOUR)) {
            return Double.NaN;
        }
        final double x2 = sq.getSumOfSquaredDeviations();
        if (!Double.isFinite(x2)) {
            return Double.NaN;
        }
        final double x4 = sq.getSumOfFourthDeviations();
        if (!Double.isFinite(x4)) {
            return Double.NaN;
        }
        // Avoid a divide by zero; for a negligible variance return NaN.
        // Note: Commons Math returns zero if variance is < 1e-19.
        final double m2 = x2 / sq.n;
        if (Statistics.zeroVariance(sq.getFirstMoment(), m2)) {
            return Double.NaN;
        }
        final double m4 = x4 / sq.n;
        if (biased) {
            return m4 / (m2 * m2) - 3;
        }
        final double n = sq.n;
        return ((n * n - 1) * m4 / (m2 * m2) - 3 * (n - 1) * (n - 1)) / ((n - 2) * (n - 3));
    }