A study prospectively examined whether sleep disordered breathing was associated with an increased risk of death from any cause in a cohort of 600 adults participating in the Sleep Heart Health Study Study participants were classified into four groups depending on the extent of their sleep disordered breathing (none, mild, moderate, or severe) The counts of deaths over the course of the study are reported for each group in the following two-way table None Mild Moderate Severe Total Death 20 40 60 80 No Death 200 50 100 100 Total 150 400 70 140 160 230 600 We want to know whether the study findings give evidence of a significant difference of the number of deaths between the different groups Set up the null hypothesis (Mo): Homogeneity of distribution of a categorical response Goodness of fittest P = Po Mac The two categorical variables are independent