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Chi-square test of association between smokers and nonsmoker

Question 1

A case-control study looked at the association of alcohol use with the occurrence of coronary heart disease (CHD). There were 300 participants in the study (150 cases and 150 controls). Of the cases, 90 participants drank alcohol; of the controls, 60 participants drank alcohol.

Design the appropriate 2x2 table, calculate and interpret the appropriate measure of association.

You suspect that the association between alcohol use and CHD might be confounded by smoking. You collect the following data:

Smokers Non-Smokers
CHD No CH CHD No CHD
Alcohol Use 80 40 10 20
No Alcohol Use 20 10 40 80

Calculate the appropriate measure of association between alcohol use and CHD in both smokers and non-smokers. Discuss whether smoking was a confounder of the association. What is the relationship of alcohol use to CHD after controlling for confounding?

Solution Summary

A case-control study looked at the association of alcohol use with the occurrence of coronary heart disease (CHD). There were 300 participants in the study (150 cases and 150 controls). Of the cases, 90 participants drank alcohol; of the controls, 60 participants drank alcohol.

Design the appropriate 2x2 table, calculate and interpret the appropriate measure of association.

You suspect that the association between alcohol use and CHD might be confounded by smoking. You collect the following data:

Smokers Non-Smokers

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