Semi-tail Units: A Universal Scale for Test Statistics and Efficiency

📅 2025-06-28
📈 Citations: 0
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🤖 AI Summary
Conventional p-values suffer from unintuitive interpretation, lack of comparability across test statistics, and difficulty in combining independent evidence. Method: We propose quantile-based standardized measures—s-values (measuring tail distance in semi-tail units, where each unit halves the tail probability) and ζ-values (a two-sided symmetric extension)—establishing the semi-tail unit as a unified scale of extremity. Our approach integrates quantile standardization, logarithmic transformation, Bahadur slope analysis, and additive evidence synthesis, enabling linear critical-value inference and direct summation of s-values for multi-source evidence integration. Contribution/Results: We introduce an interpretable logarithmic-scale s-value; construct the two-sided compatible ζ-value; and propose a novel asymptotic efficiency metric based on slope differences. Empirical validation across diverse settings—including standardized testing and poker hand distributions—demonstrates the naturalness and broad applicability of the framework.

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Machine Learning: Calibration & Uncertainty QuantificationReasoning under Uncertainty: Other Foundations of Reasoning under UncertaintyConstraint Satisfaction and Optimization: Satisfiability Modulo Theories

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📝 Abstract
We introduce $ζ$- and $s$-values as quantile-based standardizations that are particularly suited for hypothesis testing. Unlike p-values, which express tail probabilities, $s$-values measure the number of semi-tail units into a distribution's tail, where each unit represents a halving of the tail area. This logarithmic scale provides intuitive interpretation: $s=3.3$ corresponds to the 10th percentile, $s=4.3$ to the 5th percentile, and $s=5.3$ to the 2.5th percentile. For two-tailed tests, $ζ$-values extend this concept symmetrically around the median. We demonstrate how these measures unify the interpretation of all test statistics on a common scale, eliminating the need for distribution-specific tables. The approach offers practical advantages: critical values follow simple arithmetic progressions, combining evidence from independent studies reduces to the addition of $s$-values, and semi-tail units provide the natural scale for expressing Bahadur slopes. This leads to a new asymptotic efficiency measure based on differences rather than ratios of slopes, where a difference of 0.15 semi-tail units means that the more efficient test moves samples 10% farther into the tail. Through examples ranging from standardized test scores to poker hand rankings, we show how semi-tail units provide a natural and interpretable scale for quantifying extremeness in any ordered distribution.
Problem

Research questions and friction points this paper is trying to address.

Introduce quantile-based standardizations for hypothesis testing
Unify interpretation of test statistics on common scale
Provide intuitive logarithmic scale for measuring distribution tails
Innovation

Methods, ideas, or system contributions that make the work stand out.

Quantile-based standardizations for hypothesis testing
Logarithmic scale for intuitive tail area interpretation
Unified scale for all test statistics
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2024-06-25arXiv.orgCitations: 0
East Carolina University
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Paul W. Vos
Department of Public Health, East Carolina University