Identify the type of sampling used: 1. In a survey 1007 adults were called after their telephone numbers were randomly generated by a computer, and 85% of the respondents were able to correctly identify what twitter is. 2. College students are waiting in line for registration. Every eighth person in line is surveyed. 3. In 1936, literary Digest magazine mailed questionnaires to 10 million people and obtained 2,266,566 responses. The responses indicates that ALF Landon would win the presidential election. 4. During the last presidential election, CNN conducted an exit poll in which specific polling stations were randomly selected and all voters were surveyed as they left the premises