A Superintendent is interested in recruiting high students to participate in health awareness program in the school district. She obtains the entire list of high school students in the school district, and they assign each students a number from 1 to 3000 (the number of students in the school district). The Superintendent then uses a computer to randomly select the first person in the list. The computer picks the 9^th student in the list to be the first participant in the sample. The group then selects every 20^th person in the list to select the participants in the health awareness program. Is this random or non random sampling and why?