mindmap root((平均)) average is exactly or approximately the quotient obtained by dividing the sum total of a set of figures by the number of figures: scored an ~ of 85 in a series of five tests. mean may be an average, OR it may represent value midway between two extremes: annual temperature ~ of 50 degree; the tranquil ~ between misery and ecstasy. median applies to the value that represents the point at which there are as many instances above as there are below: the average of a group of persons earning 3,4,5,8,and 10 dollars a day is 6 dollars, whereas the ~ is 5 dollars. norm denotes the computed or estimated average of performance of a significantly large group, class, or grade and implies a standard of reference: scores about the ~ for 5th grade arithmetic. 注意不要写成arithmatic