Question: What's the rank when attendance was less than 18073 and having Northwestern as an opponent?
SQL: SELECT MAX("Rank") FROM "2-1888577-1" WHERE "Attendance" < 18073.0 AND "Opponent" = 'Northwestern';

Question: What's the rank for february 11, 2012 with less than 18735 in attendance?
SQL: SELECT AVG("Rank") FROM "2-1888577-1" WHERE "Date" = 'february 11, 2012' AND "Attendance" < 18735.0;