In statistics and probability theory, the median is the value that separates the higher half from the lower half of a data sample, a population, or a probability distribution. It is the middle value in a sorted list of numbers and can be more descriptive of that data set than the average. To find the median, the data points must first be arranged in order from smallest to largest. If the number of data points is odd, the median is the middle data point in the list. If the number of data points is even, the median is the average of the two middle data points in the list. The median is a measure of location that can be used when one attaches reduced importance to extreme values, typically because a distribution is skewed, extreme values are not known, or outliers are untrustworthy.