# Data audit (P1)

• File: data/schools.csv, SHA-256 0f1d8378fff2f0898762feaa08dd94d9ad04156dad6330572d98997c9005c88a
• 1000 rows × 4 columns: school_id (int, 100–139), student_id (int, 1–1000, unique), treated (int 0/1), score (float, points; 35.72–64.17, mean 50.80, sd 4.48).
• Missing values: none. Duplicate rows: 0. Duplicate student_id: 0.
• 40 schools, each exactly 25 students (balanced as stated). treated constant within every school; 20 treated / 20 control schools (500/500 students).
• No dates; no anomalies found. No information-availability violation (single permitted input).
• Exclusions: none (see out/exclusions.csv; 3 checks, 0 removed). n_raw 1000 − 0 = n_analysed 1000.