Classroom Sizes and Experience

<p>Hello! Statistics pages state that most classes in Columbia are taught with 10 to 19 students at a time, which is great by time. My first question, then, is which classes are taught as lectures with hundreds of students? Second, how is the experience in smaller classrooms? Do the professors, on average, really encourage debate? Also, how accessible are professors during out of class hours? I know the answers to the last few questions depend on and vary by professor, but what is the general experience?</p>