**Question:** Measure of dispersion among the following is:

A. Variance
B. Standard Deviation
C. Median
D. Mode

**Correct Answer:** B. Standard Deviation

**Core Concept:**

Dispersion describes the spread or variation of data points around a central measure in statistics. It helps in understanding the distribution of a set of measurements and assessing the variability within a dataset. A lower dispersion indicates a more concentrated distribution, while a higher dispersion indicates a more dispersed distribution. The measures of dispersion can be categorized into measures of spread and measures of position.

**Why the Correct Answer is Right:**

Standard Deviation (SD) is a measure of the spread of a dataset. It is calculated as the square root of the average of the squared differences from the mean. A lower standard deviation indicates a more concentrated distribution of data points around the mean, while a higher standard deviation indicates a more dispersed distribution.

**Why Each Wrong Option is Incorrect:**

A. Variance: Similar to standard deviation, variance is the average of the squared differences from the mean. However, variance is calculated as the average of squared differences, whereas standard deviation is the square root of variance.

C. Median: The median is a measure of position rather than dispersion. It is the middle value of a dataset when the values are arranged in ascending or descending order.

D. Mode: The mode is a measure of frequency rather than dispersion. It is the value(s) that appear(s) most frequently in a dataset.

**Why the Correct Answer is Right:**

Standard Deviation (SD) is a more comprehensive measure of dispersion than variance, as it is the square root of variance.

**Clinical Pearl:**

Understanding the concept of dispersion is essential in clinical practice as it helps in interpreting data and making informed decisions. For example, in medicine, standard deviation can be used to estimate the variability of a patient's vital signs or medication response, allowing clinicians to determine the expected range of normal values and identify outliers or abnormal values that may require further investigation or intervention.