is an error created by rejecting the null hypothesis when it is true.

Appeared in: AIIMS Raipur lecturer 2021

Explanation

A Type I error is defined as the incorrect rejection of a true null hypothesis.
This type of error is also known as an alpha (α) error or a "false positive.".
The probability of committing a Type I error is determined by the significance level (alpha) set by the researcher, commonly at 0.05 (5%).
This means the researcher accepts a 5% risk of concluding that an effect exists when it actually does not.

Option A: Sampling bias is an error in the process of selecting a sample, not an error in statistical decision-making about a hypothesis.
Option B: Sampling error is the natural, random variation between a sample and the population it represents. It is not an error in rejecting a hypothesis.
Option D: A Type II error is the opposite mistake. It involves failing to reject a null hypothesis when it is actually false.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Errors in statistical hypothesis testing as background academic context rather than a clinical decision trigger.
Understanding Type I and Type II errors is critical for evidence-based nursing practice. Nurses must be able to critically appraise research to determine if the conclusions are valid.
A Type I error in a clinical trial could lead to the adoption of a new, ineffective, or even harmful treatment, putting patients at risk.
A Type II error could cause a genuinely effective treatment to be overlooked and discarded, preventing patients from receiving beneficial care.

How to Approach the Question

First, identify the key terms in the question: "rejecting the null hypothesis" and "when it is true."
This is a definition-based recall question common in research methodology.
Recall the two main types of errors in hypothesis testing: Type I and Type II.
Mentally (or on paper) create a 2x2 grid: one axis for 'Null Hypothesis is True/False' and the other for 'Decision is Reject/Fail to Reject'.
Locate the cell that corresponds to 'Null is True' and 'Decision is Reject'. This cell represents a Type I error.
Compare this definition with the given options to select the correct term.

Concept Tested & Keywords

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E6 NursingResearch Polit 11e Part 1 p. 404-406

E6 NursingResearch Suresh Sharma 5e Part 1 p. 261-263

Practise the full AIIMS Raipur lecturer 2021

Attempt every question from this paper in a timed mock, then review the full solution for each one.