Identify the sampling technique used in Piliavin et al.'s (1969) subway Samaritan study and outline one demographic characteristic of the participants in this sample.
105 exam-style questions on OCR A Level Psychology Responses to people in need, covering Piliavin et al. (1969): Subway Samaritan and Levine et al. (2001): Cross-cultural altruism. Each one has a worked solution and a mark scheme showing where the marks go.