Passage Summary: A doctor argues that yoga helps people quit smoking because a study showed yoga students did just as well as people in traditional support groups, provided both groups also got counseling.

Conclusion: Hatha yoga is an effective method for helping individuals stop smoking.

Reasoning: In a study, participants who combined hatha yoga with counseling saw the same reduction in cravings and smoking as those who combined traditional self-help groups with counseling.

Analysis: The argument relies on a comparison between two groups to prove that yoga is 'powerful.' For this comparison to be meaningful, we must assume that the 'traditional self-help groups' are actually effective at reducing smoking. If those groups were totally useless, then yoga being 'as good as' them would mean yoga is also useless. Additionally, the argument assumes the counseling wasn't the only thing actually helping the participants. Look for an answer that validates the effectiveness of the comparison group or ensures the yoga itself contributed to the result.