<p>Well, averages at MIT are rarely if ever in the mid-90s. I mean, kids here are smart, but the professors expect more out of us, too! I would expect most engineering test averages to be in the 60s-70s, but that depends on the department, the class, and the professor. (For instance, a lot of chem E tests have averages in the 40s.)</p>
<p>Generally, curved classes have the average set to a B or B-, the way you have described. Still, if the average on a test did happen, by some miracle, to be 95 or something, more people would get A’s. I mean, MIT professors are challenging, not evil.</p>
<p>So the answer to your question: they curve classes by making the tests very difficult! :)</p>
<p>Incidentally, Unified is one of the relatively few classes that doesn’t curve at all. Prior to each test, the professors set the average grade for the test – as mit2007mit said, they call this hypothetical average student “Joe B.”, and he always gets a B. Sometimes Joe B. “gets” an 80, sometimes he “gets” a 60… I think most of the time he gets a 70. This system, of course, relies on the professors being able to gauge how well students will do before students take tests… it doesn’t always work, in which case lots of people fail the test. But there are many tests in each Unified semester (~11, I think), so if (when) a student fails one test, he/she has many opportunities to catch up. There is also a substantial homework component (usually two problem sets and a lab per week), so final grades aren’t just based on tests.</p>