Question Writer Manual/Quiz Options/Quiz Details/Randomization
Randomization is useful if you are expecting quiz takers to re-sit the quiz repeatedly. You can create a quiz with a large pool or bank of questions and set Question Writer to randomly select a specific number of questions from this bank. The more questions in your question bank the better as it reduces the chances that they will see the same questions time after time.
If you tick the box to use randomization, the quiz will automatically select a random set of questions from the total question bank in the root level of your quiz. You also specify how many questions you want to ask. This will be reflected in the number of questions you add to your question bank. For example you might set the value to 10. 10 questions will then be selected from the question bank for this quiz and asked in a random order. If you have 10 or fewer questions in the question bank, then all of the questions will be asked, but still in a random order.
Randomization works by generating a specified number of randomized quizzes when you publish the quiz - then one of these 'pre-randomized' quizzes is selected for the user to take when they access the quiz. You set or change the number of pre-randomized quizzes to be loaded as part of the Quiz Details set up. Remember to upload all of the files generated when you publish the quiz online.
With the Professional Version you can randomly choose which sections are used too. Quiz randomization randomizes what's directly inside the quiz and doesn't change what is inside sections or subsections. (Either a whole section will be asked or not asked and count as one selection.)
Section properties also allows you to further randomize what appears inside sections.
Randomization Seed 
If you want to create a randomized quiz and have an identical paper copy you will need to use this feature which provides "consistent randomization". When you tick the box the quiz will be randomized in the same way each time. To change the randomization, just choose a different the seed number - each seed number creates a different, but predictable randomization.