If the number of data is even, the arithmetic mean of the middle two data is the median of this set of data. Examples are as follows: Find the median of this set of data: 23, 29, 20, 32, 23, 2 1, 33, 25. Solution: First, arrange this set of data (in descending order here) and get: 20,21,23,23,25,29,32,33. Because this group of data * * * consists of 8 data, that is, n is an even number, according to the calculation method of median, the median 24, that is, the fourth number and the fifth number, is obtained.