# Stop vs noise — lesson

QA revision September 14, 2026: visible context, measurement access, and wording; see docs/exercise-qa-fixes-2026-09-14.md.

Gym heading: Sizing the order. Written before the code (Sep 7 2026); rule revised the same day (the band of the last N bars became the last completed swing; then one confirming bar each side and a 20-bar swing lookback, after a 12-bar lookback fell back to the extreme on 28% of drill reps; then the swing must sit on the stop's side of the entry). The teach screen shows this text; the answer key implements the rule in it and nothing else. Distances are in M everywhere.

Persistent header: **"Training your eye to compare a stop with recent ranges and swings."**

## Before you size

- **Noise** — The measured reference is the median high-to-low range of the last 12 bars. It describes recent ranges; it is not an upper bound on future movement.
- **The last completed swing** — For a long, the most recent swing low below the entry: a low below the lows of the bars on either side. For a short, use the mirrored swing high above entry. Search the last 20 bars; if no qualifying swing exists, use that window's extreme. A swing is a reference, not a guaranteed barrier.
- **The stop** — a distance from the entry, measured in M. Points mean nothing: 14 points is a third of the noise one night and three times the noise the next.
- **The rule** — a stop meets this drill's rule when both hold:
  1. its distance from the entry is at least **k × the median bar range of the last N bars**, and
  2. it sits **beyond the last completed swing**: below the swing low for a long, above the swing high for a short.
  Here k = 1.5 and N = 12; the swing is looked for over the last 20 bars. Fail either one and this drill classifies the stop as insufficient.
- **Why it matters at the trade** — A stop is where the idea is wrong: beyond the swing and outside the noise, not a distance you would like to lose. Compare the proposed stop with recent ranges and the marked swing before deciding on risk. Passing both tests does not establish that the stop will survive future price movement.
- **What it doesn't say** — This is a geometric classification under a stated rule. It does not estimate the chance of a stop being hit, validate an entry, or guarantee protection from noise.
- **M** — the median high-to-low range of the last 20 bars. Every distance here is in M. The number for the current chart is on the screen.
- **Confidence is a number** — Low means 40%, Medium 65%, High 90% that your call is right. Scored Brier-style: sure and wrong costs 0.81, unsure and wrong costs 0.16, sure and right costs 0.01. Being certain is as expensive as being wrong.

- **Check measurements** — Optional distances before answering: entry to stop, the 12-bar noise threshold, and entry to the marked swing, in M. Positive clearance means the stop is beyond that reference; the noise test allows equality, the swing test does not.

## The read

Three things, all in M: the recent bar ranges (how big is a normal bar right now), how far the last completed swing sits from the entry, and the proposed stop's distance from the entry. Then the question: is the stop past both?

## The rep

A chart with a proposed entry at the last close and a stop drawn on it. The last completed swing is marked. M is stated. The question, in full: **"Long (or short) from the last close, stop at the red line. Does this stop meet both the noise-distance and swing rules?"** Yes or No, with a confidence.

## The reveal

The stop distance in M, the swing's distance in M and which side of it the stop sits, k × the median range in M, the verdict, and one takeaway line. Templates:

- Survivor: **"{stop} M stop beyond the swing — meets both measured conditions; future protection is unknown."**
- Not a survivor, short of the swing: **"{stop} M stop short of the swing at {swing} M — fails the swing condition."**
- Not a survivor, beyond the swing but under the noise: **"{stop} M stop clears the swing but not {noise} M of noise — fails the measured noise-distance condition."**

Every rep ends on one of these three lines. Each is a decision: this stop goes on as drawn, or it moves, or the trade doesn't exist at that size.

## Answer key

`survives = (stopDistance >= k × median(range of last N bars)) AND (stop price is beyond the last completed swing on the stop's side)`. Swing: a low lower than the bar on either side and below the entry (long), or a high higher than the bar on either side and above the entry (short), the most recent one within the last 20 bars; swings on the wrong side of the entry are ignored; otherwise the extreme of those 20 bars. About half the reps survive (config). Some stops sit within a few percent of the threshold on purpose; the reveal shows the numbers either way.