Phyllotaxis
the spirals are counted, not admired
Concept

Robust statistic — where it appears

A summary chosen so that a few extreme values cannot move it, such as a median rather than a mean. Robustness is conditional rather than a property: a median resists a minority of outliers and stands on one when they are a majority, which is why the size of the agreeing group is reported beside every level here.

Named by 2 essays across one field — each of them below, with the objects they name alongside it.

The eight rows where the two levels disagree. Each wrecked cut's residue classes drawn as points on a circle of angle, one panel per row. A tick is one class's mean displacement. The solid radius is the densest cluster of them, which is the level this file computes; the pale radius is the median of the class means, which is the level everything in the ablation thread has been measured against. On every one of these rows the median stands on a class that is on its own, and on all 28 rows not drawn the two levels agree to within the exception tolerance of 10 degrees.

A median that is an exception

Every number in the ablation thread is measured against the value most of a wrecked stem's chains sit at, taken as a median so that a few exceptions cannot move it. On eight of thirty-six rows the median stands on a chain sitting by itself.

mechanism · Damage shape No majority and no balanced pair, over the whole census. One row per wrecked cut. The bar is the share of that row's residue classes sitting at the level they agree on, and the vertical rule is a half — a bar reaching past it has a majority and a median is safe there. The mark at the right says whether the exchange keeps that row. 15 rows are on both lists of 16 and 16, and the two part on g008/6, which is excluded and has a majority of 5 of 8, and l013/4, whose lag is 4 so that a balanced pair leaves two classes each way and a majority is arithmetically unavailable.

No majority and no pair

Whether a wrecked stem's chains agree on a level and whether its exceptions form a balanced pair are computed from different things. Sixteen rows have neither, sixteen have neither, and fifteen rows are in both — and the two they part on are the two most interesting rows in the census.

mechanism · Damage shape

Named alongside it

The objects these essays reach for when they reach for this one.

Claim testingDamage profileExceptional chainHonest limitsMeasurementNegative resultResidue classSummary statisticArtefactCensus designClassificationExchange

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