Fresh or stale — when a run is degraded

Staleness is measurable, not a mood. The band around an old quote is P·σ·√t — which gives you a threshold you can derive, and shows why one global setting is wrong across a whole book.

What you will be able to do

After this lesson you can compute the plausible band around a stale quote, derive a freshness threshold from a stated price tolerance rather than choosing one, and explain why a small error in a price becomes a large error in any difference computed from it.

Inside this lesson

Every number has a birthday
How wrong, exactly?
The error does not stay in the price
The gate is this lesson with a latch

This lesson is on Scholar

Audit includes orientation and the two-rooms lesson. The rest of the path is paid course access — still education, still not advice.

Included on Scholar · $79/month tuition.