Center of a distribution

Center is one of the features a full description of a quantitative distribution covers, alongside shape, variability, and unusual features such as outliers, gaps, or clusters. The two standard measures are the mean $\bar{x}$ (x-bar) and the median, and shape decides which one you quote, since the mean follows a long tail while the median mostly ignores it. Take the values 3, 5, 6, 8, 28: the mean is $50/5 = 10$, the median is 6, and 6 is the better summary of where a typical value sits. Pair the mean with the standard deviation and the median with the IQR so your center and spread match.