Final answer:
To minimize guessing on students' grades, a teacher should avoid tests with true or false and multiple choice questions, as these formats have higher chances of guessing. Fill in the blank and short answer questions are preferable as they require deeper knowledge.
Step-by-step explanation:
If a teacher wants to minimize guessing on students' grades, the types of tests that should be avoided are those that inherently have a higher probability of students guessing the correct answer. Tests with true or false questions and multiple choice questions are more susceptible to guessing. This is because these formats provide a limited range of possible answers, making it easier for students to select the correct answer by chance. For instance, with true or false questions, there is always a 50% chance of guessing the answer correctly. Multiple choice questions, depending on the number of choices, may also offer a relatively high probability of a correct guess.
Conversely, formats like fill in the blank and short answer questions tend to reduce the likelihood of guessing since they require students to retrieve or synthesize information without the hint of possible answers. These types of questions often demand a deeper understanding and recall of the material.