Administrators at Texas A&M University were interested in estimating the percentage of students who are the first in their family to go to college. For each scenario below, identify the type of sampling method used by the university administrators.
a) Select several dormitories at random and contact everyone living in the selected dorms.
b) Send every registered student a text containing the survey question.
c) Using a computer-based list of registered students, contact 200 freshman, 200 sophomores, 200 juniors, and 200 seniors selected at random from each class.
d) Using a computer-based list of registered students, select one of the first 25 on the list by random and then contact the student whose name is 50 names later, and then every 50 names beyond that.
e) Using a computer-based list of registered students, contact 1000 students at random.