Random effects model

A random effects model is a type of statistical model used when you have items or people that you want to compare, but there might be differences between them. For example, if you wanted to compare the test scores of students in two different classes, you might want to use a random effects model. This is because the students in each class might have different abilities or circumstances that make it hard to compare the results fairly.

In a random effects model, you would account for those differences between the classes by assigning each student a number, or "random effect," that is different from the other students. This number would represent the differences between their abilities, or the differences in their circumstances. Then, when you compare the test scores of the two classes, you would also take into account the different numbers for each student, so that the results wouldn't be affected by the differences between them.

You can think of a random effects model as a way to make sure that each student has an equal chance of doing well on the test, even if they come from different classes or don't have the same abilities and circumstances. This helps to provide more fair and accurate results.