CONCEPT:The median is the middle number in a DATA set when the numbers are listed in either ascending or descending order.If total number of observation (n) is odd then, Median = (n + 1)th/2 observationCalculation:Given data is-31, 37, 43, 42, 25, 46, 45, 39, 32Now, the given data is in ascending order- 25, 31, 32, 37, 39, 42, 43, 45, 46The median of this data is the middlemost number of this data (as the total number of data is odd)= [(9 + 1)/2]th = [10/2]th = 5th numberSo, the required median is 39.