# Contract — F2-conf-02

Question: Is the memo's claim that the OLS slope of y on x is significant at 5% still supported when uncertainty accounts for serially correlated errors? Estimand: β in the linear projection y_t = α + β x_t + u_t (full-sample OLS, intercept included). Meaningful as a projection coefficient under stationarity/weak dependence; HAC inference needs u_t x_t to be weakly dependent with finite fourth moments. Outputs: out/results.json (task_id, beta_hat, alpha_hat, se_iid, rho_resid, se_hac, hac_lags, t_hac, p_hac, beta_ci_low, beta_ci_high, memo_claim_supported, n_analysed, feasibility, feasibility_reason, data_issues, n_input_rows, random_seed), out/report.md (Question; Data and exclusions; Method; Results; Uncertainty; Limitations and open issues), out/analysis.py, out/claims.json (incl. memo-claim restatement with verdict). Information rules: only data/series.csv and data/memo.md; memo numbers can be reproduced for comparison, not taken as given. (gate_spec.json in the workspace root is not an input and was not read.) Invalidity: missing/garbled data, gaps making HAC lag order meaningless, nonstationarity making the projection ill-defined; using memo numbers as inputs.