Reply to the discussion post.Group variability - Group variability measures how much individual scores in the same group differ from each other. As the textbook states, "Group variability affects the size of the validity coefficient. Higher validity coefficients are derived from heterogeneous groups than from homogeneous groups." (Kubiszyn et al., 2024) This variable can impact test design in a positive way because it is a beneficial way to compare scores within a group and see how the class is doing overall. It shows individual differences, strengths and weaknesses on the subject, also showing a higher variability. Scoring reliability- "Scoring reliability limits test score reliability. If tests are scored unreliably, error is introduced that will limit the reliability of the test scores." (Kubiszyn et al., 2024) Some teachers will grade the same assignment or test, but grade them differently. This can affect the reliability of the test because one teacher may score things more harshly and another may score more easily, not showing the true validity of the students' scores. When scoring my tests, I will be sure to keep my grading consistent and fair for each student. Test length - "Reliability of test scores tends to decrease as tests become too easy or too difficult." (Kubiszyn et al., 2024) With test length, it is important to realize that if the test is too short, easy and everyone gets every single answer correct, then it is unreliable