Machine Learning with R

Chapter 10. Evaluating Model Performance

Many years ago, when only the wealthy could afford access to education, tests and examinations were not used to evaluate the students. Instead, they were used to judge the teachers—parents wanted to know whether their children were learning enough to justify the instructors' wages. Obviously, this practice has changed over the years. Now, such evaluations are used to distinguish between high and low-achieving students, filtering them into careers and further educational opportunities.

Given the significance of this process, a great deal of effort is invested in developing accurate student assessments. A fair assessment will have a large number of questions to cover a wide breadth of topics and reward true ...