Final answer:
An item analysis primarily determines the difficulty and item discrimination index for each exam item, essential for understanding test quality but not directly for assessing content validity and test-retest reliability.
Step-by-step explanation:
An item analysis performed on exam items can primarily determine the difficulty of each test item and the item discrimination index for each item. While content validity and test-retest reliability are crucial aspects of psychological assessments, they are not directly assessed by item analysis.
Item difficulty refers to how many test-takers answer a question correctly, where a higher percentage indicates an easier question. Item discrimination, on the other hand, looks at how well an item can differentiate between those who overall scored well and those who did not. A high discrimination index means that high scorers on the test tended to answer the item correctly, while low scorers did not, suggesting that the item is good at discriminating between different levels of ability or understanding.
Content validity involves ensuring that the test measures the entire range of the concept it's supposed to assess. Test-retest reliability measures whether the test gives consistent results over multiple administrations. Item analysis typically does not provide direct information on these aspects but can indirectly suggest areas where content coverage or stability over time may be lacking.