Which measure can provide information about the dispersion of a data set around its mean?

The standard deviation is the appropriate measure for assessing the dispersion of a data set around its mean. It reflects how far the individual data points are, on average, from the mean value of the data set. A low standard deviation indicates that the data points tend to be close to the mean, whereas a high standard deviation indicates that the data points are spread out over a wider range of values.

In contrast, other options do not serve the same function. A blob plot visually represents data but does not quantify dispersion. The coefficient of variation does express relative dispersion but does so in relation to the mean and is useful for comparison between different data sets. The median represents the middle value of a data set and does not provide information about how the data points are distributed around the mean. Thus, the standard deviation is the most direct and effective measure of dispersion concerning the mean in a data set.