[supercat]

Anti-smokers engage in some pretty amazing statistical homeopathy. Using proper statistical methods, a person who gets lung cancer having been exposed to only a trivial amount of secondhand smoke should be regarded as a data point against the proposition that secondhand smoke is significantly harmful, in that it shows that not all cases of lung cancer are attributable to SHS. To a statistical homeopathist, however, any case of cancer by anyone with any exposure whatsoever to SHS proves that SHS is dangerous. The smaller the exposure (and thus, to a proper statistician, the more tenuous the causal relationship) the stronger the proof.

[gondramB]

>>Using proper statistical methods, a person who gets lung cancer having been exposed to only a trivial amount of secondhand smoke should be regarded as a data point against the proposition that secondhand smoke is significantly harmful, in that it shows that not all cases of lung cancer are attributable to SHS. To a statistical homeopathist, however, any case of cancer by anyone with any exposure whatsoever to SHS proves that SHS is dangerous.<<

Both of the approaches are incorrect.