Repeat the previous exercise, considering another potential confounding variable€”whether the physicians smoked. The contingency table cross-classifies treatment group by smoking status.

a. Find the conditional proportions (recall Section 3.1) in the categories of this potential confounder (amount of exercise) for each treatment group. Are they similar?
b. Do you think that the randomization process did a good job of achieving balanced treatment groups in terms of this potential confounder? Explain.

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Smoking Status Treatment Never Past Current Total Aspirin 543 4373 1213 11,017 Placebo 5488 430 225 11,014