How many research assistants of Ogdon Zywicki have an average salary?
research assistant refers to the student who serves for research where the abbreviation is RA; average salary refers to salary = 'med';
SELECT COUNT(T1.prof_id) FROM RA AS T1 INNER JOIN prof AS T2 ON T1.prof_id = T2.prof_id WHERE T2.first_name = 'Ogdon' AND T1.salary = 'med' AND T2.last_name = 'Zywicki'