NSO case study: why these numbers exist
=======================================

**Why this exists:** A narrative is the easiest way to keep students oriented. This chapter frames the NSO dataset as a business story.

Learning objectives
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- Describe the NSO business in 60 seconds (what it sells, who it serves, why data matters).
- Identify the main questions Track D is trying to answer with NSO.
- Explain why a case study is useful before BYOD.

Outline
-------

The business story we’re modeling
---------------------------------

- What NSO does and what financial drivers matter (sales volume, margins, seasonality).
- What data we have and what we *don’t* have (and how that affects conclusions).

The analysis questions Track D repeats
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- Performance: what happened this period vs last period?
- Drivers: which categories/accounts explain the change?
- Risk: where are anomalies, volatility, or concentration?
- Decisions: what would you recommend based on evidence?
- Each chapter produces a small set of artifacts (CSV/PNG/JSON/MD) that support one of these questions.

Transfer to your own data
-------------------------

- The same questions apply to any small business ledger.
- BYOD lets students swap in their own exports later (see :doc:`../track_d_byod`).

Where this connects in the workbook
-----------------------------------

- :doc:`../track_d` (Track D overview)
- :doc:`../track_d_chapter_index` (where the story shows up in chapters)

.. note::

   This page is intentionally an outline right now. Expand it incrementally as we refine Track D narrative.