Literary digest voter survey, 표본의 대표성이 훼손된 고전적인 사례로 Literary Digest 史上最貴的民調 Landon-vs.-Roosevelt respondents were biased Case Study I: The 1936 Literary Digest Poll example Landon-vs.-Roosevelt Literary Digest in 1936 check how Literary Digest made a similar mistake 1936 Literary Digest poll 準確預測每年選情 reports