Nature and meaning of science

Correct answer: B. Independent confirmation is still needed because of the shared error

The same error can produce a similar wrong conclusion across many studies. Check independence as well as quantity of evidence.

Correct answer: A. It may show association but establishing causation is difficult

Without controlled intervention it is difficult to rule out other causes. Look for controlled experiments when judging causation.

Correct answer: A. Overfitting

The model may memorise specific patterns in old data without generalising. Remember the importance of testing on new data.

Correct answer: B. Low accuracy and high precision

Consistent readings show precision while constant distance from the true value shows inaccuracy. Distinguish the two.

Correct answer: A. Its falsifiability is weak

A claim adjusted to fit every outcome cannot be effectively tested. Identify clear falsifiable hypotheses.

Correct answer: B. Random assignment of participants

Direct answer: Option B, random assignment of participants. For a fair causal comparison, the treatment and control groups should be similar before the treatment begins. Random assignment gives each participant a fair chance of entering either group. With enough participants, existing differences such as ability, age, health, or motivation are more likely to be balanced between groups. Step by step: recruit participants; randomly assign them to treatment or control; apply the treatment only to the treatment group; compare outcomes; attribute differences more reasonably to the treatment, while considering other sources of error. Option B is correct because it strengthens causal inference. Option A is wrong because changing groups after seeing results can introduce manipulation and does not repair the original comparison. Option C is wrong because increasing only one group can create unequal size and does not remove starting differences. Option D is wrong because removing the control group removes the comparison needed to judge the treatment. Exam cue: unequal starting groups suggest random assignment.

Correct answer: A. Expectation effect

Knowledge of group assignment can influence expectations and behaviour. Link blinding with expectation bias.

Correct answer: A. Generalisation may be strong but causal testing may be limited

A representative sample supports external validity while non-random assignment may weaken causal inference. Distinguish sampling from assignment.

Correct answer: B. Gather evidence using different independent methods

When different methods reach the same conclusion the chance of a shared methodological error decreases. Recognise converging evidence.

Correct answer: A. A small actual change may appear very large

A large percentage from a small baseline may represent a small actual difference. Examine both relative and absolute change.

Correct answer: A. Bias from choosing a favourable outcome

Selecting the primary outcome after viewing data can increase selective reporting. Look for predefined outcome measures.

Correct answer: B. The conflict of interest should be disclosed and independent confirmation sought

Financial interests do not automatically invalidate results but independent review is needed. Examine transparency and evidence.

Correct answer: A. Operational testing is difficult

Without clear measurement criteria the explanation is difficult to test empirically. Look for operational definitions.

Correct answer: A. The instrument may be precise but not accurate

A fine scale may improve precision while systematic error reduces accuracy. Distinguish the two.

Correct answer: A. Lack of independent reproduction

Repetition within the same setup shows repeatability but not independent reproduction. Distinguish the terms.

Correct answer: B. Examine subgroup results and possible causes separately

An overall average may hide important differences among groups. Examine distributions and subgroups.

Correct answer: A. Evaluation of direct evidence and methods

Expert agreement may matter but it should be grounded in evidence. Examine both consensus and evidence.

Correct answer: A. Overgeneralisation

Making a universal claim from limited conditions goes beyond the evidence. Examine the scope of a claim.

Correct answer: A. Observer bias

Random assignment reduces group differences but assessor expectations may still affect measurement. Look for blinded assessment.

Correct answer: A. The model may be useful but its explanation should not be treated as literal truth

A model's predictive usefulness may differ from the literal truth of its assumptions. Distinguish usefulness from truth.

Correct answer: A. Time-related changes may affect the outcome

Differences in measurement timing may be confused with treatment effects. Keep measurement conditions comparable.

Correct answer: A. It provides a more balanced picture of the effect

Negative results reveal failed attempts and the real limits of an effect. Value the complete evidence picture.

Correct answer: A. A chance result may have been selected

With many analyses some unusual findings may occur by chance. Look for predefined subgroups and independent confirmation.

Correct answer: B. Examine the quality of the opposing study and the total weight of evidence

The impact of one study should be judged by its quality and the wider evidence. Examine the total weight of evidence.

Correct answer: A. Coverage bias

People without internet access were excluded so representativeness is limited. Examine sample coverage.