Average
From Encyclopædia
The average, or mean, of a set of
numbers is the sum of all the
numbers in the set divided by the total
number of elements of the set. Taking as an example the set 50, 60, 65, 70, 75, 80, 80, 85, 92, the mean is 73 (657 divided by 9). The mean should more precisely be called the arithmetic mean to distinguish it from other, more specialized types of means, such as geometric, harmonic, and weighted means.A related term is
median. The
median of a set of
numbers is a
number such that half of the elements of the set are larger and half smaller than it when the
numbers are arranged in order of size. When the
number of elements is even, there are two "middle"
numbers, and the
median is taken to be the average of those two
numbers. When the
number of elements is odd, a particular
number of the set is the middle
number, hence, the
median. The
median of the above set of
numbers is 75.Another term related to average is mode, which is the
number in a set of
numbers that occurs most frequently. The mode of the above set of
numbers is 80. If all the
numbers are different, there is no mode; if two
numbers occur most frequently, there are two modes.The mean,
median, and mode are used in the field of STATISTICS as
numbers for measuring
Central tendencies--that is, for discerning patterns in variable data. For example, physicists cannot predict with certainly how a single subatomic particle will react during an experiment. They can, however, observe and average together large
numbers of particle reactions and thereby predict tendencies of particular behavior.
