code: def get_Z(x_segment, y_segment, x_int, y_int, slope):
      
      Z = 0
      first_time = True
      for num, x in enumerate(x_segment):
          b_wiggle = get_b_wiggle(x, y_segment[num], y_int)
          z = old_div((x * abs(b_wiggle - abs(slope)) ), abs(x_int))
          Z += z
          first_time = False
      return Z
docs: input: x_segment, y_segment, x_int, y_int, slope
      output: Z (Arai plot zigzag parameter)