The study was conducted on 20 samples of Management Department students from the University of Indonesia from a population of 1000 students to nd out their average expenditure in one month of the 20 students, it was found that the average monthly expenditure was IDR 500,000 with a standard deviation of IDR 100,000. With a 95% condence interval, estimate the monthly average expenditure interval for all students of the Management Department, University of Indonesia