STDDEV_SAMP

1
SELECT STDDEV_SAMP(test_score) AS score_stddev
2
FROM sample_students;

1
SELECT question_id,
2
       STDDEV_SAMP(rating) AS rating_variation
3
FROM survey_responses
4
GROUP BY question_id;

1
SELECT 
2
  AVG(value) AS mean,
3
  STDDEV_SAMP(value) / SQRT(COUNT(*)) AS std_error
4
FROM experiment_data;