Biostatistics & Research · single question

A comparison chart shows three dental lasers: Laser 1 (negative confidence interval for treatment benefit, lower price), Laser 2 — an Erbium:YAG device (positive confidence interval excluding zero, mid-range price), and Laser 3 (negative confidence interval, higher price). Which laser should be recommended for purchase based on the statistical evidence shown?

Laser 1, because it's the cheapest
Laser 2 (the Erbium:YAG laser) — the only one with a confidence interval that excludes zero/the negative range, indicating a statistically significant favorable treatment effect, regardless of its price relative to the others
Laser 3, because higher price implies higher quality
All three are equally recommendable since price differences don't matter statistically

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Correct answer: B. Laser 2 (the Erbium:YAG laser) — the only one with a confidence interval that excludes zero/the negative range, indicating a statistically significant favorable treatment effect, regardless of its price relative to the others

A confidence interval that is entirely positive (excluding zero) indicates a statistically significant beneficial effect, while a confidence interval that includes negative values (or crosses zero) suggests the result is not statistically significant or could even reflect no real benefit. Laser 2 (Erbium:YAG) is the only device showing a clearly positive, significant effect — making it the evidence-based recommendation regardless of how its price compares to the other two options, which show no demonstrated significant benefit at all.

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