Watson-Glaser Critical Thinking Appraisal Analyzing Conclusions Questions and Answers 2 — Questions and Answers
Question 1: A study found that employees who participate in wellness programs take fewer sick days. A manager concludes that wellness programs cause employees to be healthier. Which statement best evaluates this conclusion?
- The conclusion is proven because the data is from a formal study.
- The conclusion may be flawed because healthier employees may self-select into wellness programs. (Correct answer)
- The conclusion is valid since fewer sick days directly equals better health.
- The conclusion is invalid because wellness programs never affect health outcomes.
Correct answer: The conclusion may be flawed because healthier employees may self-select into wellness programs.
Healthier employees may already be more likely to join wellness programs (selection bias), meaning the correlation does not establish causation.
This question tests your ability to evaluate a causal conclusion drawn from correlational data. The manager's conclusion assumes causation (wellness programs → health), but it is equally possible that employees who are already healthier voluntarily participate in wellness programs. This is known as selection bias or reverse causation. A valid causal conclusion requires ruling out such alternative explanations, ideally through random assignment. Therefore, option B correctly identifies the flaw without overcorrecting into the extreme denial of any effect.
Question 2: Statement: 'All mammals are warm-blooded. Dolphins are mammals.' Conclusion: 'Therefore, dolphins are warm-blooded.' Evaluate this conclusion.
- The conclusion does not follow because dolphins live in cold water.
- The conclusion follows necessarily from the given statements. (Correct answer)
- The conclusion is probably true but requires further evidence.
- The conclusion follows only if dolphins are also vertebrates.
Correct answer: The conclusion follows necessarily from the given statements.
This is a valid deductive syllogism: if all mammals are warm-blooded and dolphins are mammals, then dolphins must be warm-blooded.
This is a classic example of a valid deductive argument in the form of a categorical syllogism. The major premise states a universal property of all mammals (warm-bloodedness). The minor premise classifies dolphins as mammals. The conclusion applies the universal property to the specific case. There is no logical gap — the conclusion follows necessarily. Environmental factors like water temperature are irrelevant to the logical structure. Option A introduces an irrelevant consideration. Options C and D add conditions not required by the logical form.
Question 3: A city council reports that after installing more streetlights, crime rates dropped by 20%. A council member concludes that the streetlights reduced crime. What is the strongest challenge to this conclusion?
- Streetlights are expensive, so any benefit is outweighed by cost.
- Crime rates were already declining before streetlights were installed. (Correct answer)
- The 20% figure is too small to be meaningful.
- Streetlights only work at night, limiting their impact.
Correct answer: Crime rates were already declining before streetlights were installed.
If crime was already trending downward, the streetlights may not be the cause of the reduction — a pre-existing trend undermines the causal claim.
To evaluate whether streetlights caused the crime reduction, we must consider alternative explanations. If crime rates were already declining (a pre-existing downward trend), the 20% drop may have occurred regardless of the streetlights. This is a confounding factor that the council's conclusion ignores. Options A and D raise practical objections but do not challenge the causal logic. Option C misreads the data — a 20% drop is statistically meaningful. Option B directly challenges the inference by providing an alternative causal explanation.
Question 4: Research shows that children who eat breakfast perform better academically. A school policy maker concludes that providing free breakfasts will improve all students' grades. Which conclusion is best supported?
- Free breakfasts will definitely raise every student's grades by improving nutrition.
- Providing breakfasts may help students who previously skipped breakfast but may not affect those who already ate. (Correct answer)
- Academic performance is unrelated to nutrition, so the policy will have no effect.
- The research proves that breakfast is the only factor affecting academic performance.
Correct answer: Providing breakfasts may help students who previously skipped breakfast but may not affect those who already ate.
The benefit of breakfast likely applies mainly to students who were skipping it; those who already ate breakfast are unlikely to show additional gains.
The research establishes an association between eating breakfast and academic performance. However, the policy conclusion that ALL students will improve is too broad. Students who already eat breakfast receive no additional benefit from the program. The improvement would logically be concentrated among students who previously skipped breakfast. Option A overstates certainty. Option C contradicts the research. Option D makes an exclusivity claim unsupported by the evidence. Option B is the most logically precise conclusion grounded in the data.
Question 5: An economist states: 'Countries with higher chocolate consumption have more Nobel Prize winners per capita.' She concludes that chocolate boosts brain function. How should this conclusion be classified?
- Definitely true — the data shows a strong positive correlation.
- Likely false — the conclusion confuses correlation with causation and ignores confounding variables. (Correct answer)
- True, provided the study was peer-reviewed.
- Partially true because some ingredients in chocolate may improve memory.
Correct answer: Likely false — the conclusion confuses correlation with causation and ignores confounding variables.
Wealthier nations tend to both consume more chocolate and produce more Nobel laureates; wealth is a confounding variable, making the causal claim unfounded.
This is a textbook example of a spurious correlation. Wealthier countries have better educational systems, more research funding, and higher chocolate consumption — all driven by the same underlying factor (national wealth). Without controlling for confounders like GDP or education investment, attributing Nobel Prize rates to chocolate is logically invalid. Option A accepts the correlation as proving causation. Option C incorrectly assumes peer review validates a logical fallacy. Option D is a partial distractor — while some chocolate compounds may have mild cognitive effects, this does not validate the specific conclusion drawn from national-level correlation data.
Question 6: A doctor notices that patients prescribed a new drug recovered faster than historical records suggest. She concludes that the drug is effective. What is the primary weakness in this conclusion?
- Historical records are always accurate, so the comparison is unfair.
- There is no control group, so other factors (better nursing, newer equipment) may explain the faster recovery. (Correct answer)
- The drug must be tested on animals first before concluding it works in humans.
- Recovery speed is not a valid measure of drug effectiveness.
Correct answer: There is no control group, so other factors (better nursing, newer equipment) may explain the faster recovery.
Without a concurrent control group, improvements in standard of care, patient selection, or other factors could explain the faster recovery rather than the drug.
The doctor is comparing outcomes to historical data (a historical control), which is a weak research design. Many factors change over time: nursing protocols, hospital equipment, patient demographics, and co-administered treatments. Without a concurrent randomized control group receiving a placebo or the old standard of care, it is impossible to isolate the drug's contribution. Option A is incorrect — historical records have known limitations. Option C raises a regulatory issue, not a logical flaw. Option D is incorrect — recovery speed is a legitimate clinical endpoint. Option B correctly identifies the lack of a control group as the core methodological weakness.
Watson-Glaser Critical Thinking Appraisal Analyzing Conclusions Questions and Answers 2
A study found that employees who participate in wellness programs take fewer sick days.
A manager concludes that wellness programs cause employees to be healthier.
Which statement best evaluates this conclusion?