Between device ID of "-9215352913819630000" and "-9222956879900150000", mention the age and gender of device user who participated more events.
more events refers to MAX(COUNT(event_id));
SELECT T.age, T.gender FROM ( SELECT T2.age, T2.gender, COUNT(T1.device_id) AS num FROM events AS T1 INNER JOIN gender_age AS T2 ON T1.device_id = T2.device_id WHERE T1.device_id BETWEEN -9215352913819630000 AND -9222956879900150000 GROUP BY T2.age, T2.gender ) AS T ORDER BY T.num DESC LIMIT 1