stddevSamp

The result is equal to the square root of varSamp.

Alias: STDDEV_SAMP.

Note

This function uses a numerically unstable algorithm. If you need numerical stability in calculations, use the stddevSampStable function. It works slower but provides a lower computational error.

Syntax

stddevSamp(x)

Parameters

x: Values for which to find the square root of sample variance. (U)Int*, Float*, Decimal*.

Returned value

Square root of sample variance of x. Float64.

Example

Query:

DROP TABLE IF EXISTS test_data;
CREATE TABLE test_data
(
    population UInt8,
)
ENGINE = Log;

INSERT INTO test_data VALUES (3),(3),(3),(4),(4),(5),(5),(7),(11),(15);

SELECT
    stddevSamp(population)
FROM test_data;

Result:

┌─stddevSamp(population)─┐
│                      4 │
└────────────────────────┘

stddevSamp

Introduced in: v1.1

Returns the sample standard deviation of a numeric data sequence. The result is equal to the square root of varSamp.

Note

This function uses a numerically unstable algorithm. If you need numerical stability in calculations, use the stddevSampStable function. It works slower but provides a lower computational error.

Syntax

stddevSamp(x)

Aliases: STDDEV_SAMP

Arguments

x — Values for which to find the square root of sample variance. (U)Int* or Float* or Decimal*

Returned value

Returns the square root of sample variance of x. Float64

Examples

Computing sample standard deviation

DROP TABLE IF EXISTS test_data;
CREATE TABLE test_data
(
    population UInt8,
)
ENGINE = Log;

INSERT INTO test_data VALUES (3),(3),(3),(4),(4),(5),(5),(7),(11),(15);

SELECT
    stddevSamp(population)
FROM test_data;

┌─stddevSamp(population)─┐
│                      4 │
└────────────────────────┘

stddevSamp​

stddevSamp