1. What is the frequency and percentage of COPD patients in the severe airway limitation group in the Eckerblad et al. (2014) study?

2. What proportion of the total sample has retired? What proportion of the total sample is ill?

3. How large is the study’s total sample size? What percentage and frequency of the total sample remained in use? Display your calculations and round to the nearest whole percentage.

4. What is the total percentage of the sample with a smoking history (current or former smokers)? Is a study participant’s smoking history clinically significant? Give an explanation for your response.