1# Verification checks (P4)23- Clean re-run (deleted outputs, ran twice): results.json byte-identical -> PASS4- numpy lstsq reproduces effect_estimate -> PASS5- numpy lstsq reproduces skill coef -> PASS6- model_metric = sqrt(mean e^2) -> PASS7- CIs contain estimates -> PASS8- CI = est +/- 1.96 se -> PASS9- SE positive; RMSEs positive -> PASS10- model_metric <= baseline_metric (nested OLS same sample) -> PASS11- 1200 - removed = n_analysed -> PASS12- conclusion consistent with CI -> PASS13- table1 main row == results -> PASS14- omitted variable bias sign: skill coef<0 and corr(skill,hours)>0 imply naive<adjusted -> PASS15- OVB identity naive = b1 + b2*delta -> PASS16