Watson-Glaser Critical Thinking Appraisal Interpreting Evidence and Data Questions and Answers 4 — Questions and Answers
Question 1: A researcher finds that countries with higher chocolate consumption win more Nobel Prizes per capita. What is the correct interpretation?
- Chocolate consumption enhances cognitive performance
- This is likely a spurious correlation driven by overall national wealth (Correct answer)
- Nobel Prize committees favor chocolate-consuming nations
- Countries should increase chocolate consumption to win more prizes
Correct answer: This is likely a spurious correlation driven by overall national wealth
Wealthier nations tend to both consume more chocolate and invest more in education and research, making national wealth the underlying confounder.
Question 2: A survey of 500 hospital patients finds that 70% report poor sleep. A headline reads: 'Majority of Americans Sleep Poorly.' What is the critical flaw?
- Five hundred is too small a sample for any conclusion
- The sample is not representative — hospital patients differ significantly from the general population (Correct answer)
- Sleep quality cannot be self-reported
- The percentage should be higher to make headlines
Correct answer: The sample is not representative — hospital patients differ significantly from the general population
Sampling bias occurs when the sample group differs systematically from the population being described, invalidating generalization.
Question 3: Data shows that students who own more books score higher on reading tests. What additional evidence would best establish a causal link?
- Testimonials from students who own many books
- A controlled experiment where books are randomly assigned to students and reading scores are tracked (Correct answer)
- National averages of book ownership
- Teacher reports about student reading habits
Correct answer: A controlled experiment where books are randomly assigned to students and reading scores are tracked
Randomized controlled experiments are the gold standard for establishing causation because they control for confounding variables.
Question 4: A bar chart compares company revenue from 2019 to 2023. The y-axis starts at $950,000 rather than zero. What effect does this have on the data's interpretation?
- It makes the data more precise
- It visually exaggerates differences, making small changes appear dramatic (Correct answer)
- It is standard practice with no effect on meaning
- It reduces the apparent growth trend
Correct answer: It visually exaggerates differences, making small changes appear dramatic
A truncated y-axis amplifies visual differences, potentially misleading viewers about the actual magnitude of change.
Question 5: A study tracks 1,000 people over 10 years and finds that daily coffee drinkers live longer on average. What conclusion is most defensible?
- Coffee consumption directly extends lifespan
- Daily coffee drinking is associated with longer life, but lifestyle confounders must be considered (Correct answer)
- Everyone should drink coffee daily to live longer
- The study proves coffee is a health supplement
Correct answer: Daily coffee drinking is associated with longer life, but lifestyle confounders must be considered
Observational longitudinal data can show association, but dietary and lifestyle habits are heavily confounded with each other.
Question 6: A statistic states the average salary at a company is $95,000, but most employees earn $55,000–$65,000. What explains this discrepancy?
- The data was collected incorrectly
- A few very high executive salaries skew the mean upward, making it unrepresentative of typical earnings (Correct answer)
- The company is growing rapidly
- Employees are underreporting their salaries
Correct answer: A few very high executive salaries skew the mean upward, making it unrepresentative of typical earnings
The mean is sensitive to extreme outliers; the median would better represent the typical employee salary in a skewed distribution.
Question 7: Two towns have identical crime rates this year. Town A has 10,000 residents; Town B has 500,000 residents. What does this tell us about the absolute number of crimes?
- Both towns have the same number of crimes
- Town B has far more crimes in absolute terms despite the identical rate (Correct answer)
- Town A is more dangerous per resident
- The rate is not meaningful without knowing crime types
Correct answer: Town B has far more crimes in absolute terms despite the identical rate
Identical rates applied to vastly different population sizes produce very different absolute numbers — 1% of 500,000 far exceeds 1% of 10,000.
Watson-Glaser Critical Thinking Appraisal Interpreting Evidence and Data Questions and Answers 4
A researcher finds that countries with higher chocolate consumption win more Nobel Prizes per capita.
What is the correct interpretation?