code: def test_robust_skewness_4(self, reset_randomstate):
      x = np.random.standard_normal(1000)
      x[x > 0] *= 3
      m = np.median(x)
      s = x.std(ddof=0)
      expected = (x.mean() - m) / s
      _, _, _, sk4 = robust_skewness(x)
      assert_allclose(expected, sk4)
  
imports: import numpy
  import pandas
  from numpy.testing import assert_almost_equal, assert_raises, assert_equal, assert_allclose
  from statsmodels.stats._adnorm import normal_ad
  from statsmodels.stats.stattools import omni_normtest, jarque_bera, durbin_watson, _medcouple_1d, medcouple, robust_kurtosis, robust_skewness
label_desc: Use image node_id 16 for calling the TestStattools obj's underlying member method code with example usage: obj.test_robust_skewness_4(reset_randomstate) without return types