Typical Values. There are several common methods of selecting a typical value for data. The most common method is the average or mean. To obtain an average value, add up all your data values and divide by the number of data items.nd then select the value in the exact middle as the median. (It turns out that if the number of items is even, as in this example, there is no exact middle. 7.2 is 5 places from the front and 6 places from the back; 7.3 is 6 places from the front and 5 places from the back.