scipy-yli/tests/test_ttest.py

#   scipy-yli: Helpful SciPy utilities and recipes
#   Copyright © 2022  Lee Yingtong Li (RunasSudo)
#
#   This program is free software: you can redistribute it and/or modify
#   it under the terms of the GNU Affero General Public License as published by
#   the Free Software Foundation, either version 3 of the License, or
#   (at your option) any later version.
#
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#   but WITHOUT ANY WARRANTY; without even the implied warranty of
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#   GNU Affero General Public License for more details.
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from pytest import approx

import numpy as np
import pandas as pd

import yli

def test_ttest_ind_ol6_1():
	"""Compare yli.ttest_ind for Ott & Longnecker (2016) example 6.1"""
	
	df = pd.DataFrame({
		'Type': ['Fresh'] * 10 + ['Stored'] * 10,
		'Potency': [10.2, 10.5, 10.3, 10.8, 9.8, 10.6, 10.7, 10.2, 10.0, 10.6, 9.8, 9.6, 10.1, 10.2, 10.1, 9.7, 9.5, 9.6, 9.8, 9.9]
	})
	
	result = yli.ttest_ind(df, 'Potency', 'Type')
	
	t_expected = 0.54/(0.285*np.sqrt(1/10+1/10))
	
	assert result.statistic == approx(t_expected, abs=0.01)
	assert result.dof == 18
	assert result.delta.point == approx(0.54, abs=0.01)
	assert result.delta.ci_lower == approx(0.272, abs=0.01)
	assert result.delta.ci_upper == approx(0.808, abs=0.01)
	
	expected_summary = '''t(18) = 4.24; p < 0.001*
μ(Fresh) (SD) = 10.37 (0.32), μ(Stored) (SD) = 9.83 (0.24)
Δμ (95% CI) = 0.54 (0.27–0.81), Fresh > Stored'''
	
	assert result.summary() == expected_summary