Watson-Glaser Critical Thinking Appraisal Assessing Probability of Inferences Questions and Answers 4 — Questions and Answers
Question 1: A new medicine showed a 40% improvement rate versus 25% for placebo in a 500-patient trial. Inference: The medicine is effective.
- True
- Probably True (Correct answer)
- Insufficient Data
- Probably False
Correct answer: Probably True
A meaningfully higher rate than placebo in a substantial sample suggests probable effectiveness, though additional trials would be needed for certainty.
Question 2: The library closes at 6 PM on weekdays and 4 PM on weekends. Today is Tuesday. Inference: The library is open at 5 PM today.
- True (Correct answer)
- Probably True
- Insufficient Data
- Probably False
Correct answer: True
Tuesday is a weekday and the library closes at 6 PM, so it is definitively open at 5 PM.
Question 3: Ice cream sales and drowning rates both rise every summer. Inference: Eating ice cream causes drowning.
- True
- Probably True
- Insufficient Data
- Probably False (Correct answer)
Correct answer: Probably False
Both trends are explained by hot weather driving people to swim and buy ice cream; there is no causal link between the two.
Question 4: A school's graduation rate rose from 75% to 88% after implementing a new tutoring program. Inference: The tutoring program helped improve the graduation rate.
- True
- Probably True (Correct answer)
- Insufficient Data
- Probably False
Correct answer: Probably True
The correlation between the program's introduction and the improved rate, combined with a plausible mechanism, makes this inference probably true.
Question 5: Of 200 applicants, only those with a bachelor's degree were shortlisted. Tom does not have a bachelor's degree. Inference: Tom was not shortlisted.
- True (Correct answer)
- Probably True
- Insufficient Data
- Probably False
Correct answer: True
A bachelor's degree was a necessary condition for shortlisting, and Tom lacks it, so he was definitively not shortlisted.
Question 6: A politician's approval rating fell 20 points immediately after a controversial speech. Inference: The speech caused voters to lose confidence in the politician.
- True
- Probably True (Correct answer)
- Insufficient Data
- Probably False
Correct answer: Probably True
The immediate timing and the well-established relationship between public statements and approval shifts makes this inference probably true.
Question 7: A traffic signal was installed at an intersection last year. Accidents at that intersection dropped 60% in the following year. Inference: The traffic signal reduced accidents.
- True
- Probably True (Correct answer)
- Insufficient Data
- Probably False
Correct answer: Probably True
A large drop immediately following signal installation with a clear logical mechanism makes this inference probably true, even if other factors may also have contributed.
Watson-Glaser Critical Thinking Appraisal Assessing Probability of Inferences Questions and Answers 4
A new medicine showed a 40% improvement rate versus 25% for placebo in a 500-patient trial.
Inference: The medicine is effective.