Once a test has been administered to a student, there is an option to test only incorrect items or retest all items. Step-by-step instructions are as follows:
1. Click on a student's name and then click the "Test" button on the test to be administered: 
(Classic View)
2. If the test has been administered to this student, then the “All Questions” or “Incorrect & Not Tested” options will display: 
If the student is retested on all items, a new test session is created without changing previous test session data. Please see the Details Button Support Page for more information.
There are two possible reasons why these two test options do not display:
1. The test has never been administered to the student.
or
2. The test is on a blue or purple subject tab that is managed by your school or district. Your School or District Admin can force the option whether students should retest all questions or only the incorrect ones.