#/***********************************************************
#    normal.rb -- 正規分布
#***********************************************************/
PI = 3.14159265358979323846264

def p_nor( z )  # 正規分布の下側確率 
    z2 = z * z
    t = p = z * Math::exp(-0.5 * z2) / Math::sqrt(2 * PI)
    3.step(200, 2) do |i|
        prev = p;  t *= z2 / i.to_f;  p += t
        if (p == prev); return 0.5 + p; end
    end
    return (z > 0) ? 1 : 0
end

def q_nor( z )  # 正規分布の上側確率 
    return 1 - p_nor(z)
end

printf("正規分布の下側確率\n")
for i in 0..20
    z = 0.2 * i
    printf("%3.1f %16.14f\n", z, p_nor(z))
end

exit 0