HY — H2: story-point estimation vs historical-mean baseline
H0₂: no example-enriched configuration beats the historical-mean baseline MAE. H1₂: at least one configuration achieves a statistically significant MAE reduction ≥ 0.5 story points.
Result — H0₂ NOT REJECTED. The best configuration (qwen2.5:7b, contextual-anchoring) reaches MAE = 1.86 SP versus a baseline MAE = 2.03 SP — a 0.17 SP reduction below the 0.5 SP relevance threshold; Wilcoxon p = 0.104, r = −0.16 (N=100). The confidence interval includes zero.
Important distinction: the baseline predictor’s constant value is 4.04 SP (the historical mean story point), which is not a MAE — the baseline’s error is the 2.03 SP figure used in the test. On long-tailed story-point data, a constant-mean predictor is a surprisingly strong MAE baseline.
Source: PUMA project documentation · Traceability: corpus units
MEM-018,MEM-047,PUMA-022· reconciliation verdict G2 · Confidence: verified-at-primary-source