Implement yli.spearman

This commit is contained in:
RunasSudo 2022-12-03 20:00:29 +11:00
parent 56e16bc71d
commit fa89f2f156
Signed by: RunasSudo
GPG Key ID: 7234E476BF21C61A
3 changed files with 57 additions and 2 deletions

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@ -49,3 +49,18 @@ def test_pearsonr_ol11_16():
assert result.statistic.point == approx(0.606, abs=0.001)
assert result.statistic.ci_lower == approx(0.314, abs=0.001)
assert result.statistic.ci_upper == approx(0.793, abs=0.001)
def test_spearman_ol11_17():
"""Compare yli.spearman for Ott & Longnecker (2016) example 11.17"""
df = pd.DataFrame({
'Profit': [2.5, 6.2, 3.1, 4.6, 7.3, 4.5, 6.1, 11.6, 10.0, 14.2, 16.1, 19.5],
'Quality': [50, 57, 61, 68, 77, 80, 82, 85, 89, 91, 95, 99]
})
result = yli.spearman(df, 'Profit', 'Quality')
assert result.statistic.point == approx(0.874, abs=0.001)
expected_summary = 'ρ (95% CI) = 0.87 (0.60–0.96); p < 0.001*' # NB: The confidence intervals are unvalidated
assert result.summary() == expected_summary

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@ -20,7 +20,7 @@ from .descriptives import auto_descriptives
from .distributions import beta_oddsratio, beta_ratio, hdi, transformed_dist
from .io import pickle_read_compressed, pickle_read_encrypted, pickle_write_compressed, pickle_write_encrypted
from .regress import OrdinalLogit, PenalisedLogit, logit_then_regress, regress, vif
from .sig_tests import anova_oneway, auto_univariable, chi2, mannwhitney, pearsonr, ttest_ind
from .sig_tests import anova_oneway, auto_univariable, chi2, mannwhitney, pearsonr, spearman, ttest_ind
def reload_me():
import importlib

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@ -23,7 +23,7 @@ import functools
import warnings
from .config import config
from .utils import Estimate, Interval, PValueStyle, as_2groups, check_nan, convert_pandas_nullable, fmt_p
from .utils import Estimate, Interval, PValueStyle, as_2groups, as_numeric, check_nan, convert_pandas_nullable, fmt_p
# ----------------
# Student's t test
@ -718,6 +718,46 @@ def pearsonr(df, dep, ind, *, nan_policy='warn'):
return PearsonRResult(statistic=Estimate(result.statistic, ci.low, ci.high), pvalue=result.pvalue)
# --------------------
# Spearman correlation
class SpearmanResult:
def __init__(self, statistic, pvalue):
self.statistic = statistic
self.pvalue = pvalue
def __repr__(self):
if config.repr_is_summary:
return self.summary()
return super().__repr__()
def _repr_html_(self):
return '<i>ρ</i> ({:g}% CI) = {}; <i>p</i> {}'.format((1-config.alpha)*100, self.statistic.summary(), fmt_p(self.pvalue, PValueStyle.RELATION | PValueStyle.HTML))
def summary(self):
"""
Return a stringified summary of the Spearman correlation
:rtype: str
"""
return 'ρ ({:g}% CI) = {}; p {}'.format((1-config.alpha)*100, self.statistic.summary(), fmt_p(self.pvalue, PValueStyle.RELATION))
def spearman(df, dep, ind, *, nan_policy='warn'):
# Check for/clean NaNs
df = check_nan(df[[ind, dep]], nan_policy)
# Ensure numeric, factorising categorical variables as required
ind, _ = as_numeric(df[ind])
dep, _ = as_numeric(df[dep])
# Compute Spearman's rho
result = stats.spearmanr(ind, dep)
# Compute confidence interval
ci = stats._stats_py._pearsonr_fisher_ci(result.correlation, len(dep), 1 - config.alpha, 'two-sided')
return SpearmanResult(statistic=Estimate(result.correlation, ci.low, ci.high), pvalue=result.pvalue)
# ----------------------------
# Automatic selection of tests