For items 19-21 use the following data set: In a clinical trial, 9 out of 29 asthmatics taking a new drug continue to have asthma attacks 3 months later, whereas 12 of 74 asthmatics using a new...

Extracted text: For items 19-21 use the following data set: In a clinical trial, 9 out of 29 asthmatics taking a new drug continue to have asthma attacks 3 months later, whereas 12 of 74 asthmatics using a new breathing exercise continue to have asthma attacks. 19. Calculate RR for asthma attack cases among new drug users. В. 0.23 C. 0.28 A. 0.16 D. 0.31 20. Calculate RR for asthma attack cases among those who are using the breathing exercise. A. 0.16 В. 0.23 C. 0.28 D. 0.31 21. Which new treatment approach is more effective in preventing asthma attacks? A. Breathing exercise B. New drug and breathing exercise C. New drug regimen D. Placebo