Which statistical measure is used to indicate the variability of a set of data?

• A. Mean
• B. Mode
• C. Standard Deviation
• D. Median

Answer: (C)

The standard deviation is the statistical measure that indicates the variability of a set of data. It quantifies the amount of variation or dispersion in a dataset. When the standard deviation is low, it signifies that the data points tend to be close to the mean (average), while a high standard deviation indicates that the data points are spread out over a wider range of values.

By assessing variability, the standard deviation provides insight into the level of consistency or fluctuation present in the data. Understanding this measure is crucial for interpreting the reliability and predictability of data in various fields, including counseling, where it may relate to client behavior or assessment results.

In contrast, the mean provides an average of the data, the mode identifies the most frequently occurring value, and the median represents the middle value when a dataset is ordered; none of these measures convey the same information about the spread or variability in the data as the standard deviation does.