Is this a proper way to present Back and Next buttons in Android app?

As part of a Quiz app, in which users have to go through a set of questions, I need to provide the ability to:

  1. Quit the quiz
  2. Go to next question
  3. Go (back) to the previous question

I am trying to implement some Material Design principles into my design. Is this a legit way of doing this - having the back and next buttons in the bottom bar? Please advise.

see screenshot