What does a small standard deviation indicate about a data set?

A small standard deviation indicates that the data points in a set are closely clustered around the mean. This means that the values do not vary widely and tend to be near the average value of the data set. When standard deviation is small, it reflects a high level of consistency among the data points, suggesting that most of the observations fall within a narrow range. Therefore, this characteristic helps in understanding the overall distribution of the data, reinforcing the idea that a small standard deviation signifies less spread in the values.

While the other options may describe different aspects of data sets or specific conditions, they do not accurately capture the meaning of a small standard deviation. For instance, the mean being equal to the median pertains to the shape of the distribution, and the presence of outliers relates to the data points that remain far from the main cluster, which can exist regardless of the standard deviation size.