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

What is a Type I error in hypothesis testing?

ASelecting too many participantsBMeasuring an exposure impreciselyCConcluding an effect exists when it does notDMissing a real effect that exists

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

The answer and the reasoning

C. Concluding an effect exists when it does not

A Type I error is a false-positive conclusion: rejecting the null hypothesis even though no true effect or difference exists.

Option by option

A. Selecting too many participants
Large samples alone do not define Type I error.
B. Measuring an exposure imprecisely
Imprecision may contribute to error but is not its definition.
C. Concluding an effect exists when it does not (correct)
Correct: a false positive is Type I error.
D. Missing a real effect that exists
A false negative is Type II error.

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.

Questions about this PSM question

What is the answer to this PSM question?

The best answer is C, Concluding an effect exists when it does not. A Type I error is a false-positive conclusion: rejecting the null hypothesis even though no true effect or difference exists.

Why is "Selecting too many participants" not the answer?

Large samples alone do not define Type I error.

Why is "Measuring an exposure imprecisely" not the answer?

Imprecision may contribute to error but is not its definition.

Why is "Missing a real effect that exists" not the answer?

A false negative is Type II error.

What concept does this question test?

It tests Biostatistics in PSM. The correct option holds because: Correct: a false positive is Type I error.

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.