Hey !
In a previous course, I've had a teacher who took a similar approach with the quizzes as you have decided to do it ; not graded and for personal training. It was a great think as it really helps us to grave into the stone the newly acquired knowledge.
On this note, I would like to suggest some improvements that would greatly improve the usage of quizzes and make the experience better and more enjoyable :
-Give us the right to review our answers after finishing a quiz, for example I have finished mine, but I postponed for a later period to write down the answers as additional exercises. After submitting the attempt and closing the quiz, I couldn't access anymore to the page that displays my answers and the correction which is very unfortunate. It may come in handy to come back to it during revisions.
-Allow us the reattempt a quiz as many times as we wish. After a first attempt, we can check the answers that are incorrect and not spoil ourselves, getting a new chance to reattempt the quiz for the questions that we have failed and think about them again.
If you add all of those improvements, it would be very beneficial from an educational standpoint towards all the students :D
