CREATE TABLE candidate (candidate_id DECIMAL, people_id DECIMAL, poll_source TEXT, date TEXT, support_rate DECIMAL, consider_rate DECIMAL, oppose_rate DECIMAL, unsure_rate DECIMAL)
CREATE TABLE people (people_id DECIMAL, sex TEXT, name TEXT, date_of_birth TEXT, height DECIMAL, weight DECIMAL)

which gender got the highest average uncertain ratio.
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
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 NULLS LAST LIMIT 1