What does standard deviation measure in a data set?

Standard deviation measures the spread or variation of data points in a data set. It quantifies how much individual data points deviate from the mean (average) of the dataset. A lower standard deviation indicates that the data points tend to be closer to the mean, while a higher standard deviation suggests that the data points are more spread out over a wider range of values. This concept is crucial in statistics because it helps to understand the variability and distribution of the data, allowing for better interpretation and analysis.

In contrast, the other options deal with different statistical concepts. Central tendency refers to measures like mean, median, and mode which reflect the center of the data. Frequency pertains to how often certain values occur in the data set. The difference between median and mode specifically looks at two measures of central tendency rather than the variability of the data itself.