FTB-C000482 / Statistical method

Sample-versus-Population Deviation

Sample-versus-Population Deviation is the denominator distinction between n-minus-one and n standard-deviation calculations.

Also known asstandard-deviation denominator choice

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Definitions

In plain terms

Two platforms can use the same closes and window yet disagree because one uses sample deviation and the other population deviation.

Technical

Reconciliation must compare degrees of freedom before rounding; the difference is greatest in short windows and disappears only asymptotically.

Scope

Neither denominator should be inferred from an unlabeled chart or generic function name.

Examples

  • A reviewer traces Sample-versus-Population Deviation from aligned inputs through its first-ready row and edge cases before accepting a displayed value.

Common misconceptions

  • Neither denominator should be inferred from an unlabeled chart or generic function name.

Concept relationships

Prerequisites

Related

Where this concept is used

Evidence and governance

  1. TA-Lib Bollinger Bands TA-Lib · first party technical publication

    Supports: preferred label, short definition, technical definition

    Limits: TA-Lib permits moving-average variants beyond the local close-SMA and population-deviation contract.

  2. Measures of Scale NIST/SEMATECH · official standard

    Supports: preferred label, short definition, technical definition

    Limits: The statistical reference does not define Bollinger Bands or validate financial forecasts from price dispersion.

Reviewed by
fintech-builder-batch-009
Last reviewed
2026-07-30
Next review
2027-07-30
Record status
published