Biostatistics: practice question

A PSM question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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PSM · Biostatistics

Sample item

In an observational health study, what does confounding mean?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. Distortion of exposure-outcome association by a third factor

A confounder is associated with exposure and outcome and is not on the causal pathway, distorting the observed association unless controlled.

Option by option

  • A. Random chance variation only

    Random variation affects precision.

  • B. Systematic measurement calibration

    Calibration concerns measurement error.

  • C. Distortion of exposure-outcome association by a third factor (correct)

    Correct: third-factor distortion defines confounding.

  • D. Loss of participants after enrolment

    Loss to follow-up is attrition bias.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More PSM questions

Questions about this PSM question

What is the answer to this PSM question?

The best answer is C, Distortion of exposure-outcome association by a third factor. A confounder is associated with exposure and outcome and is not on the causal pathway, distorting the observed association unless controlled.

Why is "Random chance variation only" not the answer?

Random variation affects precision.

Why is "Systematic measurement calibration" not the answer?

Calibration concerns measurement error.

Why is "Loss of participants after enrolment" not the answer?

Loss to follow-up is attrition bias.

What concept does this question test?

It tests Biostatistics in PSM. The correct option holds because: Correct: third-factor distortion defines confounding.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Biostatistics?

Practise biostatistics with small calculations until sensitivity, predictive values and risk measures are automatic. Then use the flashcards and the other PSM questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.