studentTTestOneSample

Introduced in: v25.10.0

Applies the one-sample Student’s t-test to determine whether the mean of a sample differs from a known population mean.

Normality is assumed. The null hypothesis is that the sample mean equals the population mean.

The optional confidence_level enables confidence interval calculation.

Notes:

At least 2 observations are required; otherwise the result is (nan, nan) (and intervals if requested are nan).
Constant or near-constant input will also return nan due to zero (or effectively zero) standard error.

See Also

Syntax

studentTTestOneSample([confidence_level])(sample_data, population_mean)

Parameters

confidence_level — Optional. Confidence level for confidence intervals. Float in (0, 1). Float*

Arguments

sample_data — Sample data. Integer or Float or Decimal
population_mean — Known population mean to test against (usually a constant). (U)Int* or Float* or Decimal

Returned value

Returns a tuple with two or four elements (if confidence_level is specified): calculated t-statistic, calculated p-value (two-tailed), [calculated confidence-interval-low], [calculated confidence-interval-high]. Confidence intervals are for the sample mean at the given confidence level. Tuple(Float64, Float64) or Tuple(Float64, Float64, Float64, Float64)

Examples

Without confidence interval

CREATE TABLE t (value Float64) ENGINE = Memory;
INSERT INTO t VALUES (20.3), (21.1), (21.9), (21.7), (19.9), (21.8);

SELECT studentTTestOneSample()(value, 20.0) FROM t;

┌─studentTTestOneSample(value, 20.)─────────┐
│ (3.2378108288009266,0.023005151817711324) │
└───────────────────────────────────────────┘

With confidence interval (95%)

SELECT studentTTestOneSample(0.95)(value, 20.0) FROM t;

┌─studentTTestOneSample(0.95)(value, 20.)────────────────────────────────────────┐
│ (3.2378108288009266,0.023005151817711324,20.230116092352564,22.00321724098077) │
└────────────────────────────────────────────────────────────────────────────────┘

See Also