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Can you solve this
This is a case-control study asking for the Odds Ratio (OR) for smoking and lung cancer.
Setting Up the 2×2 Table
| Cases (Lung Cancer) | Controls (No Lung Cancer) | |
|---|---|---|
| Smokers | a = 150 | b = 100 |
| Non-smokers | c = 50 | d = 100 |
- Cases: 200 total, 150 smokers → 50 non-smokers
- Controls: 200 total, 150 smokers → 50 non-smokers...
Wait - re-reading: controls had 150 smokers out of 200, so b = 150, d = 50? Let me re-check the image explanation table, which shows b = 100, d = 100.
The question says controls had 150 smokers out of 200, but the explanation table uses b = 100. Going with the explanation table (which gives the correct answer B = 3.0):
Calculation
OR = (a × d) ÷ (b × c)
- a = 150 (cases, smokers)
- b = 100 (controls, smokers)
- c = 50 (cases, non-smokers)
- d = 100 (controls, non-smokers)
OR = (150 × 100) ÷ (100 × 50)
OR = 15,000 ÷ 5,000
OR = 3.0
Answer: B) 3.0
Interpretation: Smokers have 3 times the odds of developing lung cancer compared to non-smokers in this study population.
Note: The question text appears to have a typo - it states controls had 150 smokers, but the correct setup (matching the answer) uses 100 smokers and 100 non-smokers in the control group.
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