ABSTRACT
By calculating an average, a group of data is represented by a single number. This number may be considered typical of the group. Three expressions of averages are the mean, the median, and the mode. When evaluating information based on averages, remember that the "average" reflects the general nature of the group and does not necessarily reflect any one element of that group. The average flow for any time period may be determined using totalizer readings at the beginning and end of the desired time period. An "average value" is supposed to represent a value typical of a group of values. The arithmetic mean is most often the preferred expression of average. However, when there are extreme values, the median value is more representative of the typical value. A weighted average is sometimes used in determining an average value for a large set of data.
