how to calculate a median value
In some statistical analyses, the median is a better predictor of the expected value for a set of observations than the mean (average). To calculate the median, in the simplest terms, if you have an odd number (n) of items in an ordered set, the median is the value where (n+1)/2 is the row containing the median value. If there is an even number of rows, the value is the average (mean) of the two values appearing in the n/2 and the 1+n/2 rows.