{"races": [{"race_id": "2020_Turkish_Grand_Prix", "race": "2020 Turkish", "season": 2020, "n": 139, "mean": 55.539568345323744, "sd": 17.176303815527792, "se": 1.4568750749150519, "calibration": "leave-one-race-out"}, {"race_id": "2023_Spanish_Grand_Prix", "race": "2023 Spanish", "season": 2023, "n": 128, "mean": 54.3984375, "sd": 18.309125048963804, "se": 1.6183133099643479, "calibration": "leave-one-race-out"}, {"race_id": "2023_United_States_Grand_Prix", "race": "2023 United States", "season": 2023, "n": 121, "mean": 54.16528925619835, "sd": 15.77284365031104, "se": 1.4338948773010036, "calibration": "leave-one-race-out"}, {"race_id": "2023_Mexico_City_Grand_Prix", "race": "2023 Mexico City", "season": 2023, "n": 128, "mean": 52.0390625, "sd": 16.763242127377797, "se": 1.481675272867606, "calibration": "leave-one-race-out"}, {"race_id": "2023_Qatar_Grand_Prix", "race": "2023 Qatar", "season": 2023, "n": 116, "mean": 51.26724137931034, "sd": 19.09791366047913, "se": 1.7731967678294052, "calibration": "leave-one-race-out"}, {"race_id": "2021_Abu_Dhabi_Grand_Prix", "race": "2021 Abu Dhabi", "season": 2021, "n": 111, "mean": 51.22522522522522, "sd": 16.23569900702064, "se": 1.5410243529144547, "calibration": "leave-one-race-out"}, {"race_id": "2023_Miami_Grand_Prix", "race": "2023 Miami", "season": 2023, "n": 123, "mean": 50.6260162601626, "sd": 17.737653841605255, "se": 1.5993503859217586, "calibration": "leave-one-race-out"}, {"race_id": "2023_Monaco_Grand_Prix", "race": "2023 Monaco", "season": 2023, "n": 165, "mean": 50.46060606060606, "sd": 17.44167665338328, "se": 1.3578326859065568, "calibration": "leave-one-race-out"}, {"race_id": "2023_Dutch_Grand_Prix", "race": "2023 Dutch", "season": 2023, "n": 130, "mean": 47.96153846153846, "sd": 14.502733878163399, "se": 1.271973904971894, "calibration": "leave-one-race-out"}, {"race_id": "2023_Japanese_Grand_Prix", "race": "2023 Japanese", "season": 2023, "n": 120, "mean": 47.891666666666666, "sd": 20.22778445329317, "se": 1.8465356389034957, "calibration": "leave-one-race-out"}, {"race_id": "2023_Italian_Grand_Prix", "race": "2023 Italian", "season": 2023, "n": 130, "mean": 47.44615384615385, "sd": 16.353339597046574, "se": 1.434282763604088, "calibration": "leave-one-race-out"}, {"race_id": "2019_German_Grand_Prix", "race": "2019 German", "season": 2019, "n": 101, "mean": 47.039603960396036, "sd": 17.99830618657564, "se": 1.790898401642929, "calibration": "leave-one-race-out"}], "n_races": 12, "n_2023": 9, "within_season_spread": 6.95, "cross_era_spread": 8.5, "contrasts": [{"comparison": "2023 Spanish vs 2023 Italian (both 2023)", "diff": 6.95, "z": 3.22, "p": 0.0013, "bonferroni_alpha": 0.0063, "survives": true}], "era_comparison": {"mean_2023": 50.7, "mean_pre2023": 51.27, "diff": -0.57, "z": -0.54, "p": 0.5867, "systematic_era_effect": false}, "verdict": "Holding the season fixed barely changes the picture: races from 2023 alone spread 7.0 points, against 8.5 across all seasons. Recording era does not explain the separation. 2023 Spanish vs 2023 Italian (both 2023) differs by +7.0 (p=0.00130), surviving Bonferroni correction. And there is no systematic offset between eras (-0.6 points, p=0.5867), which is the confound tested directly."}