In statistical terms, what does 'sigma' typically represent?

In statistical terminology, 'sigma' refers to the symbol used to denote the standard deviation of a population, not the sum of all observations in a data set. The standard deviation is a measure of the amount of variation or dispersion of a set of values. It quantifies how much the values in a distribution deviate from the mean.

When examining the other options, the first choice incorrectly describes sigma as a measure of central tendency, which typically includes statistics like the mean, median, or mode but not the standard deviation. The third option incorrectly identifies sigma as a specific data point, while the fourth choice describes the range of values within a distribution, which refers to the difference between the maximum and minimum values rather than measurement of spread like sigma indicates. Therefore, selecting a choice that describes sigma alongside its correct statistical role provides clarity on its significance in understanding data variations.