Sales Trend Analysis

I have several Excel and CSV files containing our historical sales figures, and I need a clear picture of the underlying trends. The task is straightforward: import or connect to the data, clean anything that might distort the results, then surface the key patterns—seasonality, product-level movements, regional differences, and any notable spikes or dips over time.

You’re free to work in the environment you know best—Excel’s Power Query and Pivot Charts, Python with pandas and matplotlib, R with ggplot2, or a BI tool such as Tableau or Power BI—as long as the final output can be delivered in two parts:

• A concise written summary (PDF or doc) that explains the main trends in plain language and highlights actionable insights.
• Visuals: charts or dashboards that let me drill into time periods and categories without having to rerun code.

Please keep the workflow reproducible (share any scripts or notebook files you use) so I can refresh the analysis with future data drops.