这是一个真实的例子,来自一项医学研究<ref>C. R. Charig; D. R. Webb; S. R. Payne; O. E. Wickham (29 March 1986). "Comparison of treatment of renal calculi by open surgery, percutaneous nephrolithotomy, and extracorporeal shockwave lithotripsy". ''Br Med J (Clin Res Ed)''. '''292''' (6524): 879–882. doi:10.1136/bmj.292.6524.879. PMC 1339981. <nowiki>PMID 3083922</nowiki>.</ref>,比较两种治疗肾结石的成功率<ref>Steven A. Julious and Mark A. Mullee (1994-12-03). "Confounding and Simpson's paradox". BMJ. 309 (6967): 1480–1481. doi:10.1136/bmj.309.6967.1480. PMC 2541623. <nowiki>PMID 7804052</nowiki></ref>。 | 这是一个真实的例子,来自一项医学研究<ref>C. R. Charig; D. R. Webb; S. R. Payne; O. E. Wickham (29 March 1986). "Comparison of treatment of renal calculi by open surgery, percutaneous nephrolithotomy, and extracorporeal shockwave lithotripsy". ''Br Med J (Clin Res Ed)''. '''292''' (6524): 879–882. doi:10.1136/bmj.292.6524.879. PMC 1339981. <nowiki>PMID 3083922</nowiki>.</ref>,比较两种治疗肾结石的成功率<ref>Steven A. Julious and Mark A. Mullee (1994-12-03). "Confounding and Simpson's paradox". BMJ. 309 (6967): 1480–1481. doi:10.1136/bmj.309.6967.1480. PMC 2541623. <nowiki>PMID 7804052</nowiki></ref>。 |