class MoreMath::NormalDistribution

def inverse_probability(p)

NormalDistribution for the probability +p+.
Returns the inverse cumulative probability value of the 
def inverse_probability(p)
  case
  when p <= 0
    -1 / 0.0
  when p >= 1
    1 / 0.0
  when (p - 0.5).abs <= Float::EPSILON
    @mu
  else
    begin
      NewtonBisection.new { |x| probability(x) - p }.solve(nil, 1_000_000)
    rescue
      0 / 0.0
    end
  end
end