mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-12-14 02:12:21 +00:00
74 lines
2.6 KiB
Markdown
74 lines
2.6 KiB
Markdown
---
|
||
slug: /en/sql-reference/aggregate-functions/reference/mannwhitneyutest
|
||
sidebar_position: 161
|
||
sidebar_label: mannWhitneyUTest
|
||
---
|
||
|
||
# mannWhitneyUTest
|
||
|
||
Applies the Mann-Whitney rank test to samples from two populations.
|
||
|
||
**Syntax**
|
||
|
||
``` sql
|
||
mannWhitneyUTest[(alternative[, continuity_correction])](sample_data, sample_index)
|
||
```
|
||
|
||
Values of both samples are in the `sample_data` column. If `sample_index` equals to 0 then the value in that row belongs to the sample from the first population. Otherwise it belongs to the sample from the second population.
|
||
The null hypothesis is that two populations are stochastically equal. Also one-sided hypothesises can be tested. This test does not assume that data have normal distribution.
|
||
|
||
**Arguments**
|
||
|
||
- `sample_data` — sample data. [Integer](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md) or [Decimal](../../../sql-reference/data-types/decimal.md).
|
||
- `sample_index` — sample index. [Integer](../../../sql-reference/data-types/int-uint.md).
|
||
|
||
**Parameters**
|
||
|
||
- `alternative` — alternative hypothesis. (Optional, default: `'two-sided'`.) [String](../../../sql-reference/data-types/string.md).
|
||
- `'two-sided'`;
|
||
- `'greater'`;
|
||
- `'less'`.
|
||
- `continuity_correction` — if not 0 then continuity correction in the normal approximation for the p-value is applied. (Optional, default: 1.) [UInt64](../../../sql-reference/data-types/int-uint.md).
|
||
|
||
**Returned values**
|
||
|
||
[Tuple](../../../sql-reference/data-types/tuple.md) with two elements:
|
||
|
||
- calculated U-statistic. [Float64](../../../sql-reference/data-types/float.md).
|
||
- calculated p-value. [Float64](../../../sql-reference/data-types/float.md).
|
||
|
||
|
||
**Example**
|
||
|
||
Input table:
|
||
|
||
``` text
|
||
┌─sample_data─┬─sample_index─┐
|
||
│ 10 │ 0 │
|
||
│ 11 │ 0 │
|
||
│ 12 │ 0 │
|
||
│ 1 │ 1 │
|
||
│ 2 │ 1 │
|
||
│ 3 │ 1 │
|
||
└─────────────┴──────────────┘
|
||
```
|
||
|
||
Query:
|
||
|
||
``` sql
|
||
SELECT mannWhitneyUTest('greater')(sample_data, sample_index) FROM mww_ttest;
|
||
```
|
||
|
||
Result:
|
||
|
||
``` text
|
||
┌─mannWhitneyUTest('greater')(sample_data, sample_index)─┐
|
||
│ (9,0.04042779918503192) │
|
||
└────────────────────────────────────────────────────────┘
|
||
```
|
||
|
||
**See Also**
|
||
|
||
- [Mann–Whitney U test](https://en.wikipedia.org/wiki/Mann%E2%80%93Whitney_U_test)
|
||
- [Stochastic ordering](https://en.wikipedia.org/wiki/Stochastic_ordering)
|