Analyse a dataset with an audit trail

Analyse the attached [FILE TYPE] dataset to answer: [QUESTION].

Before calculating, describe the schema, row count, missingness, duplicate keys, invalid values and likely measurement issues. Define every metric and denominator. Keep a transformation log showing each cleaning step and how many rows it affects. Use robust summaries, check important segments, and test whether apparent patterns could be caused by sample size or missing data.

Return: executive summary, methods, findings, tables or charts, anomalies, limitations, and reproducible calculation steps. Never silently discard data or claim causation from correlation.