studentTTest

Introduced in: v21.1.0

Applies Student’s t-test to samples from two populations.

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 means of populations are equal. Normal distribution with equal variances is assumed.

See Also

Syntax

studentTTest([confidence_level])(sample_data, sample_index)

Parameters

confidence_level — Optional. Confidence level in order to calculate confidence intervals. Float

Arguments

sample_data — Sample data. Integer or Float or Decimal
sample_index — Sample index. Integer

Returned value

Returns a tuple with two or four elements (if the optional confidence_level is specified): calculated t-statistic, calculated p-value, [calculated confidence-interval-low], [calculated confidence-interval-high]. Tuple(Float64, Float64) or Tuple(Float64, Float64, Float64, Float64)

Examples

Basic usage

CREATE TABLE student_ttest (sample_data Float64, sample_index UInt8) ENGINE = Memory;
INSERT INTO student_ttest VALUES (20.3, 0), (21.1, 0), (21.9, 1), (21.7, 0), (19.9, 1), (21.8, 1);

SELECT studentTTest(sample_data, sample_index) FROM student_ttest;

┌─studentTTest(sample_data, sample_index)───┐
│ (-0.21739130434783777,0.8385421208415734) │
└───────────────────────────────────────────┘

See Also