In what follows use any of the following tests/procedures: Regression, confidence intervals, one-sided t-test, or two-sided t-test. All the procedures should be done with 5% P-value or 95% confidence interval. The empirical literature suggests that class absenteeism undermines students’ academic performance and that an enforced mandatory attendance policy may be beneficial. Open Attendance data. Using data on 90 second-year students enrolled in a Statistics course, test if students who are assiduous in attending lectures have higher final grades than students who are usually absent.