varSamp

Introduced in: v1.1.0 Calculate the 样本方差 of a data set. The 样本方差 is calculated using the formula:

\frac{\Sigma{(x - \bar{x})^2}}{n-1}

Where:

$x$ is each individual data point in the data set
$\bar{x}$ is the arithmetic mean of the data set
$n$ is the number of data points in the data set

The function assumes that the input data set represents a sample from a larger population. If you want to calculate the variance of the entire population (when you have the complete data set), you should use varPop instead.

该函数使用数值不稳定的算法。如果计算中需要数值稳定性，请使用 varSampStable 函数。该函数运行速度较慢，但计算误差更小。

Syntax

varSamp(x)

Aliases: VAR_SAMP Arguments

x — The population for which you want to calculate the 样本方差. (U)Int* or Float* or Decimal*

Returned value Returns the 样本方差 of the input data set x. Float64 Examples Computing sample variance

Query

DROP TABLE IF EXISTS test_data;
CREATE TABLE test_data
(
    x Float64
)
ENGINE = Memory;

INSERT INTO test_data VALUES (10.5), (12.3), (9.8), (11.2), (10.7);

SELECT round(varSamp(x),3) AS var_samp FROM test_data;

Response

┌─var_samp─┐
│    0.865 │
└──────────┘

最后修改于 2026年7月23日

varSampStable计算数据集的样本方差。与 `varSamp` 不同，此函数采用数值稳定的算法。虽然运行较慢，但计算误差更低。

​varSamp

varSamp