Database: dorm_1
Question: Find the average age of students who are living in the dorm with the maximum capacity.
SQL: select avg(t1.age) from student as t1 join lives_in as t2 on t1.stuid  =  t2.stuid join dorm as t3 on t3.dormid  =  t2.dormid where t3.student_capacity  =  (select max(student_capacity) from dorm)