code: def test_oneway_effectsize():
      # examole 3 in Steiger 2004 Beyond the F-test, p. 169
      F = 5
      df1 = 3
      df2 = 76
      nobs = 80
  
      ci = confint_noncentrality(
          F, (df1, df2), alpha=0.05, alternative="two-sided"
      )
  
      ci_es = confint_effectsize_oneway(F, (df1, df2), alpha=0.05)
      ci_steiger = ci_es.ci_f * np.sqrt(4 / 3)
      res_ci_steiger = [0.1764, 0.7367]
      res_ci_nc = np.asarray([1.8666, 32.563])
  
      assert_allclose(ci, res_ci_nc, atol=0.0001)
      assert_allclose(
          ci_es.ci_f_corrected, res_ci_steiger, atol=0.00006
      )
      assert_allclose(ci_steiger, res_ci_steiger, atol=0.00006)
      assert_allclose(ci_es.ci_f**2, res_ci_nc / nobs, atol=0.00006)
      assert_allclose(ci_es.ci_nc, res_ci_nc, atol=0.0001)
  
imports: import numpy
  from numpy.testing import assert_allclose, assert_equal
  import pytest
  from statsmodels.regression.linear_model import OLS
  import statsmodels.stats.power
  import statsmodels.stats.oneway
  from statsmodels.stats.oneway import confint_effectsize_oneway, confint_noncentrality, effectsize_oneway, anova_oneway, anova_generic, equivalence_oneway, equivalence_oneway_generic, power_equivalence_oneway, _power_equivalence_oneway_emp, f2_to_wellek, fstat_to_wellek, wellek_to_f2
  from statsmodels.stats.robust_compare import scale_transform
  from statsmodels.stats.contrast import wald_test_noncent_generic, wald_test_noncent, _offset_constraint
label_desc: Use image node_id 1 for calling a global function with example usage: test_oneway_effectsize() without return types