code: def test_standardize_ols():
      np.random.seed(123)
      nobs = 20
      x = 1 + np.random.randn(nobs, 4)
      exog = np.column_stack((np.ones(nobs), x))
      endog = exog.sum(1) + np.random.randn(nobs)
  
      res2 = OLS(endog, exog).fit()
      transf = StandardizeTransform(exog)
      exog_st = transf(exog)
      res1 = OLS(endog, exog_st).fit()
      params = transf.transform_params(res1.params)
      assert_allclose(params, res2.params, rtol=1e-13)
  
imports: import numpy
  from numpy.testing import assert_allclose, assert_equal
  from scipy import stats
  from statsmodels.regression.linear_model import OLS
  from statsmodels.tools.transform_model import StandardizeTransform
label_desc: Use image node_id 2 for calling a global function with example usage: test_standardize_ols() without return types