Which of the following is a measure of dispersion?

Appeared in: Daman & Diu Staff Nurse - 2018

Explanation

Standard deviation is a primary measure of dispersion, also known as variability or spread.
It quantifies how much the values in a dataset deviate from the mean (average).
A larger standard deviation signifies greater variability in the data, while a smaller one indicates that data points are clustered closely around the mean.
Other measures of dispersion include range and variance.

Option A: Mean is a measure of central tendency, not dispersion. It represents the average value of a dataset.
Option B: Mode is a measure of central tendency. It identifies the most frequently occurring value in a dataset.
Option D: Median is a measure of central tendency. It is the middle value of a dataset when it is ordered from least to greatest.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Measures of Dispersion vs. Central Tendency as background academic context rather than a clinical decision trigger.
Nurses use statistical concepts to interpret clinical data and research findings. For example, understanding the standard deviation of a patient's blood pressure readings over time can indicate stability (low SD) or volatility (high SD).
In evidence-based practice, nurses must be able to read research articles, which frequently report results using mean, median, and standard deviation to describe the study population and outcomes.
What if? If a group of patients' fasting blood sugar levels has a mean of 110 mg/dL with a very high standard deviation, it suggests that while the average is borderline, many patients have values that are either very low or very high, indicating poor overall glycemic control within the group and the need for individualized interventions.

How to Approach the Question

First, identify the key term in the question: 'measure of dispersion'.
Define 'measure of dispersion' in your mind. It refers to how spread out or varied the data is.
Next, evaluate each option against this definition.
Recall or determine the category for each option. 'Mean', 'Mode', and 'Median' are all measures of central tendency, which describe the 'center' of the data.
'Standard deviation' is the classic measure of how data is spread around the mean.
Therefore, 'Standard deviation' is the only option that fits the definition of a measure of dispersion.

Concept Tested & Keywords

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E6 NursingResearch Sukhpal Kaur pp. 459-461, 463-465, 440-442

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