LNAT Science 4 — Questions and Answers
Question 1: A pharmaceutical company funds a study that finds its own drug to be effective. An independent study finds no effect. Which principle best explains why the independent study should be weighted more heavily?
- Independent research is always conducted by more qualified scientists
- Funding bias can consciously or unconsciously influence study design, analysis, and publication (Correct answer)
- The pharmaceutical company study used too small a sample
- Independent studies always use better statistical methods
Correct answer: Funding bias can consciously or unconsciously influence study design, analysis, and publication
Funding bias is a well-documented phenomenon where financial interest can skew study design, data interpretation, and selective reporting, reducing the credibility of sponsored research.
Question 2: A scientist proposes a theory that can explain all possible observations, including contradictory ones. According to Popper's philosophy of science, this theory is:
- Exceptionally powerful because it is never wrong
- Unfalsifiable and therefore not genuinely scientific (Correct answer)
- The gold standard for a scientific theory
- Valid as long as it is internally consistent
Correct answer: Unfalsifiable and therefore not genuinely scientific
Popper argued that a genuine scientific theory must make predictions that could in principle be proven false; a theory compatible with any outcome is unfalsifiable and thus unscientific.
Question 3: Researchers test a new fertilizer by applying it to 50 randomly selected farms while 50 others serve as controls. Yields are 15% higher on treated farms. Which factor most strengthens the validity of this result?
- The farms were randomly assigned, reducing systematic differences between groups (Correct answer)
- The researchers chose the best-performing farms for the treatment group
- The yield increase was measured only at the end of the season
- The study was conducted in a single geographic region
Correct answer: The farms were randomly assigned, reducing systematic differences between groups
Random assignment of farms to treatment and control groups is the key feature that reduces confounding and strengthens the causal inference.
Question 4: A passage claims that because no scientist has definitively proven climate change will cause catastrophic harm, governments should not act on it. This argument relies on which flawed premise?
- That scientific certainty must be 100% before policy action is warranted (Correct answer)
- That climate change is caused by natural factors alone
- That governments are incapable of implementing environmental policy
- That scientists disagree about whether greenhouse gases exist
Correct answer: That scientific certainty must be 100% before policy action is warranted
The argument demands a certainty threshold that science never provides; policy decisions routinely and legitimately act on probabilistic evidence under uncertainty.
Question 5: A study shows that people who own cats are less likely to suffer from depression. A journalist writes: 'Cats cure depression.' Which inference error does the headline make?
- It overstates the finding by claiming causation from correlational data and by using 'cure' rather than 'reduce risk' (Correct answer)
- It correctly summarises the statistical finding
- It understates the finding because cats also reduce anxiety
- It is acceptable because journalists must simplify complex data
Correct answer: It overstates the finding by claiming causation from correlational data and by using 'cure' rather than 'reduce risk'
The headline commits two errors: inferring causation from correlation, and using 'cure'—implying complete elimination—when the data only show a statistical association.
Question 6: An experiment finds that a new reading programme raises test scores by an average of 5 points. The p-value is 0.03. What does this tell us?
- There is a 3% probability that the null hypothesis is true
- If there were no real effect, there is a 3% chance of observing a difference this large or larger by chance (Correct answer)
- The programme is educationally significant and should be adopted immediately
- 97% of students will improve their reading scores with this programme
Correct answer: If there were no real effect, there is a 3% chance of observing a difference this large or larger by chance
A p-value of 0.03 means that, assuming no true effect, the probability of obtaining these results by chance alone is 3%, indicating statistical significance, not the probability that the null hypothesis is true.
Question 7: A passage argues that because ancient civilisations used herbal medicine without modern science, herbal remedies must be effective. Which flaw does this argument contain?
- It commits the appeal to tradition fallacy, confusing historical use with proven efficacy (Correct answer)
- It correctly applies the principle of accumulated human wisdom
- It provides a falsifiable hypothesis about herbal medicine
- It commits an ad hominem attack on modern medicine
Correct answer: It commits the appeal to tradition fallacy, confusing historical use with proven efficacy
The appeal to tradition (argumentum ad antiquitatem) mistakes long use for evidence of effectiveness; historical practice does not constitute clinical proof of efficacy.
