Quiz questions can be randomized through the quiz settings.
When editing a quiz, select Quiz Settings.
In the quiz settings, turn on Show Random Questions and enter the number of questions.
If the number of questions enter is equal to or more than the number of questions available, all questions will be shown. Ideally, the number of questions would be less than the total number of questions in the quiz. For example, if the quiz has 20 total questions, enter a smaller number such as 10.