CREATE TABLE "attendance_history" (
  "rank" real,
  "attendance" real,
  "opponent" text,
  "result" text,
  "date" text
);

Question: What's the rank when attendance was less than 18,073 and having Northwestern as an opponent?
SQL: SELECT MAX("rank") FROM "attendance_history" WHERE "attendance"<'18,073' AND "opponent"='northwestern';

Question: What's the rank for February 11, 2012 with less than 18,735 in attendance?
SQL: SELECT AVG("rank") FROM "attendance_history" WHERE "date"='february 11, 2012' AND "attendance"<'18,735';