Biostatistics & Research · single question
A study has a 95% Confidence Interval (CI) of (-3.41, 16.41). What is a reasonable conclusion?
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Correct answer: A. Results are NOT statistically significant; null hypothesis cannot be rejected
A 95% CI of (-3.41, 16.41) INCLUDES ZERO. If the CI includes zero, there is NO statistically significant difference — we cannot reject the null hypothesis. Statistical significance requires the CI to EXCLUDE zero. Since 0 falls within this interval, the data are consistent with no effect.
- A. Incorrect. Results are NOT significant because the CI includes zero.
- B. Incorrect. The results are NOT significant BECAUSE the range includes 0 — this is a wrong conclusion.
- C. CORRECT. CI of (-3.41, 16.41) includes 0 → results are not statistically significant → null hypothesis cannot be rejected.
- D. Incorrect. The reason for non-significance is the CI INCLUDING ZERO — not merely that the lower bound is negative.
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