Let's lооk аt hypоthesis testing between two cаtegoricаl variables: Research Question: Do the odds of having a stroke increase if you inhale second hand smoke? A case-control study of non-smoking stroke patients and controls of the same age and occupation are asked if someone in their household smokes. Variables: There are two different categorical variables (Stroke patient vs control and whether the subject lives in the same household as a smoker). Living with a smoker (or not) is the natural explanatory variable and having a stroke (or not) is the natural response variable in this situation. Match the null and alternative hypotheses for the scenario described above.