ClickHouse/docs/zh/sql-reference/aggregate-functions/reference/varpop.md

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2021-02-02 12:00:41 +00:00
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# varPop(x) {#varpopx}
Calculates the amount `Σ((x - x̅)^2) / n`, where `n` is the sample size and `x̅`is the average value of `x`.
In other words, dispersion for a set of values. Returns `Float64`.
!!! note "Note"
This function uses a numerically unstable algorithm. If you need [numerical stability](https://en.wikipedia.org/wiki/Numerical_stability) in calculations, use the `varPopStable` function. It works slower but provides a lower computational error.