humble opinion- 2nd lecture - testing hypothesis
 

Excellent course.
I have observed while watching 2nd lecture that (especially non-campus) students were lost about Hoeffding Inequality and it's application to hypothesis set using multiple-bins analogy.
If hypotheses test example is given over a finite hypothesis set (i.e. asking several experts for a credit evaluation function) , discussion about Hoeffding Inequality and multiple bins would be easier to grasp.