In mathematics, an average is a measure of the "middle" or "typical" value of a data set. It is thus a measure of central tendency.
In the most common case, the data set is a list of numbers. The average of a list of numbers is a single number intended to typify the numbers in the list. If all the numbers in the list are the same, then this number should be used. If the numbers are not the same, the average is calculated by combining the numbers from the list in a specific way and computing a single number as being the average of the list.
Many different descriptive statistics can be chosen as a measure of the central tendency of the data items. These include the arithmetic mean, the median, and the mode. Other statistics, such as the standard deviation and the range, are called measures of spread and describe how spread out the data is.
The most common statistic is the arithmetic mean, but depending on the nature of the data other types of central tendency may be more appropriate. For example, the median is used most often when the distribution of the values is skewed with a small number of very high or low values, as seen with house prices or incomes. It is also used when extreme values are likely to be anomalous or less reliable than the other values (e.g. as a result of measurement error), because the median takes less account of extreme values than the mean does.
Famous quotes containing the word average:
“The average Southerner has the speech patterns of someone slipping in and out of consciousness. I can change my shoes and socks faster than most people in Mississippi can speak a sentence.”
—Bill Bryson (b. 1951)
“In 70 he married again, and I having, voluntarily, assumed the legal guilt of breaking my marriage contract, do cheerfully accept the legal penaltya life of celibacybringing no charge against him who was my husband, save that he was not much better than the average man.”
—Jane Grey Swisshelm (18151884)
“Here is a golden Rule.... Write legibly. The average temper of the human race would be perceptibly sweetened, if everybody obeyed this Rule!”
—Lewis Carroll [Charles Lutwidge Dodgson] (18321898)