Equation 2 · Part 6 · Hominin Evolution and Deep Prehistory: A First-Principles Introduction

Symbol P_3

\hat{f} = \frac{\sum_{i} (P_2(i) - P_1(i))\,(P_4(i) - P_1(i))}{\sum_{i} (P_3(i) - P_1(i))\,(P_4(i) - P_1(i))}

P_3

What this part means

$P_3$ occurs below the fraction bar. The quantity above the bar is divided by this expression; zero is excluded as a denominator.

Its job in the formula

$P_3$ occurs below the fraction bar. The quantity above the bar is divided by this expression; zero is excluded as a denominator.

Full expressionSymbol P_3Article meaning

The passage around this formula

…a candidate-admixed population, a comparison population without the admixture, and the archaic source, respectively. The estimator exploits a simple logic: if population $P_2$ has interbred with the archaic lineage $P_4$ and $P_3$ has not, $P_2$ should share systematically more rare variants with $P_4$ than $P_3$ does, in proportion to the fraction of its genome that traces to that admixture event. This is why admixture claims in the literature are reported as percentages with confidence intervals rather than as a binary…

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Learn the underlying idea

A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.

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Sources cited in the article section

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