SELECT department, STDEV(salary) AS salary_spread FROM employees GROUP BY department; 
-- Output:
department    salary_spread
-----------   -------------
Sales         12450.75
Engineering   15678.23
Marketing      9876.44
HR             7234.89
Finance       11567.32

SELECT category, STDDEV_POP(price) AS price_deviation FROM products GROUP BY category; 
-- Output:
category        price_deviation
--------------  ---------------
Electronics          245.67
Clothing             34.89
Home & Garden        89.45
Books                12.34
Sports Equipment    156.78

SELECT course_id, STDDEV_SAMP(score) AS score_spread FROM student_scores GROUP BY course_id;
-- Output:
course_id    score_spread
---------    ------------
CS101        8.45
MATH201      12.67
ENG102       6.89
PHYS301      14.23
CHEM201      10.56