Sleep apnea is a disorder in which you have one or more pauses in breathing or shallow breaths while you sleep. In a cross-sectional study of 320 individuals who suffer from sleep apnea, it was found that 192 had gum disease. Note: In the general population, about 17.5% of individuals have gum disease.
(a) What does it mean for this study to be cross-sectional?
(b) What is the variable of interest in this study? Is it qualitative or quantitative? Explain.
(c) Estimate the proportion of individuals who suffer from sleep apnea who have gum disease with 95% confidence. Interpret your result?