Data collected in the study investigating the links between health risks and income found that 30% of low-income adults, 22% of middle-income adults, and 14% of high-income adults are smokers.
Would you say that smoking status and income level are independent? Why/why not?
Given only the information above, can you determine the overall proportion of adults in this study who smoke? If so, what is the proportion? If not, what other information would you need?