Ejemplo n.º 1
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 def testTValue(self):
   """Tests calculation of the t-value using Welch's formula."""
   # Results can be verified by directly plugging variables into Welch's
   # equation (e.g. using a calculator or the Python interpreter).
   stats1 = ttest.SampleStats(mean=0.299, var=0.05, size=150)
   stats2 = ttest.SampleStats(mean=0.307, var=0.08, size=165)
   # Note that a negative t-value is obtained when the first sample has a
   # smaller mean than the second, otherwise a positive value is returned.
   self.assertAlmostEqual(-0.27968236, ttest._TValue(stats1, stats2))
   self.assertAlmostEqual(0.27968236, ttest._TValue(stats2, stats1))
Ejemplo n.º 2
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 def testTValue(self):
     """Tests calculation of the t-value using Welch's formula."""
     # Results can be verified by directly plugging variables into Welch's
     # equation (e.g. using a calculator or the Python interpreter).
     stats1 = ttest.SampleStats(mean=0.299, var=0.05, size=150)
     stats2 = ttest.SampleStats(mean=0.307, var=0.08, size=165)
     # Note that a negative t-value is obtained when the first sample has a
     # smaller mean than the second, otherwise a positive value is returned.
     self.assertAlmostEqual(-0.27968236, ttest._TValue(stats1, stats2))
     self.assertAlmostEqual(0.27968236, ttest._TValue(stats2, stats1))
Ejemplo n.º 3
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 def testTValue_ConstantSamples_ResultIsInfinity(self):
   """If there is no variation, infinity is used as the t-statistic value."""
   stats = ttest.SampleStats(mean=1.0, var=0, size=10)
   self.assertEqual(float('inf'), ttest._TValue(stats, stats))
Ejemplo n.º 4
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 def testTValue_ConstantSamples_ResultIsInfinity(self):
     """If there is no variation, infinity is used as the t-statistic value."""
     stats = ttest.SampleStats(mean=1.0, var=0, size=10)
     self.assertEqual(float('inf'), ttest._TValue(stats, stats))