The mean and the median can be calculated to help you find the "center" of a data set. The mean is the best estimate for the actual data set, but the median is the best measurement when a data set contains several outliers or extreme values.
I we consider her running times as an arithmetic series with common difference: 43.13 - 43.1 = -.03/2 = -.015, Shelly's time in the fourth race will be 43.1 - .015 = 43.085.
