stddevSamp

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 │
└────────────────────────┘