A study reports a correlation coefficient of r = -0.82 between physical activity levels and fasting blood glucose in a sample of 50 adults. Which interpretation is most accurate?
- A There is a strong inverse correlation between physical activity and blood glucose ✓
- B There is a weak positive correlation between physical activity and blood glucose
- C Physical activity causes a reduction in blood glucose
- D The relationship is not statistically significant
Correct answer: A. There is a strong inverse correlation between physical activity and blood glucose
Explanation
B correlation coefficient of -0.82 indicates a strong inverse (negative) relationship: as physical activity increases, blood glucose tends to decrease. The magnitude (0.82) indicates strength close to the maximum of 1.0. Correlation does not establish causation, so option C overstates the finding. Statistical significance cannot be determined from r alone without knowing the p-value or confidence interval.
Reference: Biostatistics: A Foundation for Analysis in the Health Sciences, 10th ed.
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