What is the average capability of students with less than a 2.5 GPA?
average capability = AVG(capability); gpa < 2.5;
SELECT CAST(SUM(T1.capability) AS REAL) / COUNT(T1.student_id) FROM RA AS T1 INNER JOIN student AS T2 ON T1.student_id = T2.student_id WHERE T2.gpa < 2.5