STDDEV_SAMP

1
SELECT
2
  survey_question,
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  AVG(response_score) as avg_score,
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  STDDEV_SAMP(response_score) as score_variability,
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  COUNT(*) as response_count
6
FROM `project.dataset.survey_responses`
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GROUP BY survey_question
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ORDER BY score_variability DESC;

1
SELECT
2
  experiment_group,
3
  AVG(conversion_value) as avg_value,
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  STDDEV_SAMP(conversion_value) as value_stddev,
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  COUNT(*) as sample_size,
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  STDDEV_SAMP(conversion_value) / SQRT(COUNT(*)) as standard_error
7
FROM `project.dataset.ab_test_results`
8
GROUP BY experiment_group;

1
SELECT
2
  product_line,
3
  AVG(weight_grams) as mean_weight,
4
  STDDEV_SAMP(weight_grams) as weight_stddev,
5
  AVG(weight_grams) - 1.96 * STDDEV_SAMP(weight_grams) / SQRT(COUNT(*)) as ci_lower,
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  AVG(weight_grams) + 1.96 * STDDEV_SAMP(weight_grams) / SQRT(COUNT(*)) as ci_upper
7
FROM `project.dataset.production_samples`
8
GROUP BY product_line;