Critical Thinking and Problem Solving
The Critical Thinking and Problem Solving section asks you to reason rather than recall: find the conclusion of an argument, identify the assumption, judge whether the evidence supports the claim, and solve short constraint and pattern problems.
Tools
- Find the conclusion first, then the premises offered for it.
- Valid means the conclusion must follow from the premises; sound means the premises are also true in reality.
- An assumption is an unstated premise the argument needs in order to work.
- Correlation is not causation - look for a third factor (confounder).
- Check the sample: who was asked, how many, and whether they represent the population.
- Name the fallacies: hasty generalisation, false dilemma, ad hominem, appeal to tradition, circular reasoning.
- For puzzles: draw a table, work backwards from the answer, eliminate options, and check units.
Worked example
A council surveys 40 households on Betio and finds 32 (80%) support a ban on plastic bags. It announces: 'Most i-Kiribati want the ban.' Reasoning: The arithmetic is right - 80% of 40 is 32 - but the inference is not. Betio is the densest, most urban islet, and 40 households is a small, non-random group; outer-island households, a large share of the population, are missing. The conclusion needs a sample drawn across island groups, large enough to reduce chance error, with neutral question wording. As stated, it is a hasty generalisation from a biased sample.
Traps that cost marks
Reversing 'if P then Q' into 'if Q then P'; rejecting a claim because of who made it; treating one example as proof of a general rule; accepting a percentage without asking 'percentage of how many?'