I have taken stat2.1x and concurrently took stat2.2x with this JH class.
If you wanna learn Stats the right way, I suggest you take the Edx offering and stay away from this one. The class was basically a class on Greek letters ! You would be surprised if you saw any numbers or any intuitive explanation of the subject matter.
The class did not asses properly; For one It was not very hard to get good grades even if you have very little understanding (I can say this about another online course i took, but not from JH).
When you take a course that you can do well in even though you do not get MOST of the subject matter, then you know there is something wrong.
I suggest Stat2.1x, .2x and the upcoming .3x from BerkeleyX (edX).. Amazing course to say the least