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Equation 21 · Part 3 · Evolutionary Biology and Ecology in Practice: An Advanced Technical Guide

Symbol S

N^e≈13 (r^2−1S)\hat{N}_e \approx \frac{1}{3\,(\hat{r}^2 - \tfrac{1}{S})}
SS

What this part means

the sample size.

Its job in the formula

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

Where the article explains it

where r^2\hat{r}^2 is the mean squared correlation of allele frequencies across pairs of loci observed in the sample, and S is the sample size, with the 1/S term correcting for the sampling bias that a finite number of genotyped individuals introduces into r^2\hat{r}^2 even when the true population NeN_e is large.

The passage around this formula

…estimator around, in the form most commonly used for the single-sample method: N^e≈13 (r^2−1S)\hat{N}_e \approx \frac{1}{3\,(\hat{r}^2 - \tfrac{1}{S})}. where r^2\hat{r}^2 is the mean squared correlation of allele frequencies across pairs of loci observed in the sample, and S is the sample size, with the 1/S term correcting for the sampling bias that a finite number of genotyped individuals introduces into r^2\hat{r}^2 even when the true population NeN_e is large. The practical consequence practitioners have to internalize: r^2\hat{r}^2 is estimated with noise from a finite…

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Learn the underlying idea

A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.

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Sources cited in the article section

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