What is the sex of the candidate who had the highest unsure rate?
SELECT t1.sex FROM people AS t1 JOIN candidate AS t2 ON t1.people_id  =  t2.people_id GROUP BY t1.sex ORDER BY avg(t2.unsure_rate) DESC LIMIT 1
sex of the candidate = t1.sex; highest unsure rate = MAX(avg(t2.unsure_rate)); unsure rate refers to t2.unsure_rate;