The expression "(X - μ)" represents the difference between a specific value, denoted as X, and the mean or average value, represented by μ. In statistics, X can be any individual data point in a dataset, while μ is calculated by summing all data points and dividing by the total number of points. This difference helps to understand how far a particular value deviates from the average. This concept is essential in various statistical analyses, including calculating the standard deviation and variance. By examining "(X - μ)", researchers can assess the spread of data and identify outliers, which are values significantly different from the mean.