Which of the following is NOT a measure of central tendency?

The standard deviation is indeed not a measure of central tendency; rather, it is a measure of variability or dispersion in a data set. Measures of central tendency, which include the mean, median, and mode, are statistical tools used to describe the center or typical value of a data set.

The mean is calculated by summing all data points and dividing by the total number of points, providing an average value. The median is the middle value when the data points are arranged in order, which represents the central point of a distribution. The mode is the most frequently occurring value in a data set, highlighting the most common score. In contrast, standard deviation quantifies how spread out the data points are around the mean, indicating the degree of variability rather than centrality. Thus, the correct answer clearly distinguishes standard deviation from measures of central tendency.