-- Database schema
| businesses : business_id [ INTEGER ] primary_key , name [ TEXT ] , address [ TEXT ] , city [ TEXT ] , postal_code [ TEXT ] , latitude [ REAL ] , longitude [ REAL ] , phone_number [ INTEGER ] , tax_code [ TEXT ] , business_certificate [ INTEGER ] , application_date [ DATE ] , owner_name [ TEXT ] , owner_address [ TEXT ] , owner_city [ TEXT ] , owner_state [ TEXT ] , owner_zip [ TEXT ] | inspections : business_id [ INTEGER ] inspections.business_id = businesses.business_id , score [ INTEGER ] , date [ DATE ] , type [ TEXT ] | violations : business_id [ INTEGER ] violations.business_id = businesses.business_id , date [ DATE ] , violation_type_id [ TEXT ] , risk_category [ TEXT ] , description [ TEXT ] |
-- -- What is the average score of the establishments owned by the owner with the highest number of establishments?

SELECT AVG(T1.score) FROM inspections AS T1 INNER JOIN businesses AS T2 ON T1.business_id = T2.business_id GROUP BY T2.owner_name ORDER BY COUNT(T2.business_id) DESC LIMIT 1;