设x为长对角线，y为短对角线，h为高，面积为 h * [根号(x^2-h^2)+根号(y^2-h^2)]/2
range is the difference of the largest number and the smallest number in the set of data. Standard deviation shows the fluctuation of the data around the arithmetic mean (average). When range is wider, standard deviation would be bigger.
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2008-7-24 14:02:00
楼主