1. What is the definition of pack years of smoking? Is there a significant difference in pack years of smoking between the groups with moderate and severe airway limitation? Give an explanation for your response.

2. What were the top four psychological symptoms reported by this COPD patient population? How many of these people had these symptoms? Was there a statistically significant difference in psychological symptoms between the groups with moderate and severe airway limitation?

3. What percentage of the total sample used short-acting Î2 2 -agonists, and how frequently did they do so? Display your calculations and round them to the nearest whole percentage.

4. Is there a significant difference in the use of short-acting Î2 2 -agonists between the groups with moderate and severe airway restriction? Give an explanation for your response.