Which of the following is not a measure of variability?

Appeared in: ISRO- 2016

Explanation

The median is a measure of central tendency, which identifies the central point of a dataset.
It represents the middle value when the data is arranged in ascending or descending order.
Unlike measures of variability, the median does not describe the spread, dispersion, or variation of the data points.
The question asks for the option that is NOT a measure of variability, making the median the correct choice.

Option B: Variance is a fundamental measure of variability.
Option C: Standard deviation is the most commonly used measure of variability.
Option D: The range is the simplest measure of variability.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Distinguishing between measures of central tendency and measures of variability in descriptive statistics as background academic context rather than a clinical decision trigger.
Understanding the difference between central tendency and variability is crucial for interpreting patient data. For example, a patient's average (mean) blood pressure might be normal, but high variability (large standard deviation) in readings could indicate cardiovascular instability.
In research, nurses use measures of variability to determine if the effects of an intervention are consistent across a patient group. A small standard deviation suggests a consistent effect, while a large one indicates varied responses.
What if? If a nurse is monitoring blood glucose levels, a stable median is good, but a wide range (high variability) between readings, even with a normal median, could indicate poor glycemic control and risk of both hypoglycemia and hyperglycemia.

How to Approach the Question

First, carefully read the question and identify the negative keyword 'not'. This means you are looking for the option that does not fit the category 'measure of variability'.
Recall the two main types of descriptive statistics: measures of central tendency and measures of variability.
Categorize each option: a) Central Tendency: describes the center of the data (e.g., mean, median, mode). b) Variability/Dispersion: describes the spread of the data (e.g., range, variance, standard deviation).
Evaluate each option against these categories.
Median is the middle value, a measure of central tendency.
Variance, standard deviation, and range all describe how spread out the data is.

Concept Tested & Keywords

Concept Tested: Distinguishing between measures of central tendency and measures of variability in descriptive statistics.
Stem keywords: measure of variability, statistics
Lead-in keywords: not
Negative lead-in flag: The question asks to identify the option that is NOT a measure of variability.

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E6 NursingResearch Sukhpal Kaur pp. 440-442, 451-453

E6 Comprehensive Textbook of Community Health Nursing for BSc Nursing Students Part 2 — Subpart B (pp 276-535 of 550) p. 21-23

Practise the full ISRO- 2016

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