The website for the International Association of Amateur Basketball Officials has a link to practice tests and quizzes to prepare for the 2015-16 certification exam. Go to IAABO's website (IAABO.org) and click on IAABO RefSchool on the left side to enter the study tool.
There is an initial subscription fee of $25 for the American high school or international version or $35 for both versions. Officials may renew their subscription for $6 every season. Local IAABO boards can purchase 20 or more subscriptions for an initial fee of $20 for either version or $30 for both versions. IAABO RefSchool offers quizzes by rule and keyword as well as practice exams.