A study reports a Pearson correlation coefficient of r = -0.85 between age and forced expiratory volume in one second among adults. The most accurate interpretation is:
- A There is a weak inverse relationship between age and lung function
- B There is a strong inverse linear relationship between age and lung function ✓
- C Ageing causes an 85 percent decline in lung function
- D The two variables are unrelated
Correct answer: B. There is a strong inverse linear relationship between age and lung function
Explanation
Pearson r ranges from -1 to +1 and measures the strength and direction of a linear association. A value of -0.85 indicates a strong negative linear relationship. Correlation never establishes causation, which eliminates option C, and the magnitude 0.85 rules out options A and D. Note also that r says nothing about agreement between methods, for which other statistics are used.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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