标题: 求一道GWD数学 [打印本页] 作者: 小鱼good 时间: 2010-3-22 22:24 标题: 求一道GWD数学 A certain characteristic in a large population has a distribution that is symmetric about the mean m.If 68 percent of the distribution lies within one standard deviation d of the mean, what percent of the distribution is less than m +d ?
A.16%
B.32%
C.48%
D.84%
E.92% XDJM们，没看懂题意啊，帮忙解答一下吧 作者: 切尔西 时间: 2010-3-22 23:49
你的答案怎么四个红的，一个黑的，答案该是D的吧？作者: cindytim 时间: 2010-3-23 02:14
帮顶， 也想知道作者: tracyforever 时间: 2010-3-23 11:20
求教！作者: slickdeals 时间: 2010-3-23 11:41 A certain characteristic in a large population has a distribution that is symmetric about the mean m.If 68 percent of the distribution lies within one standard deviation d of the mean, what percent of the distribution is less than m +d ?
The distribution is a symmetric about the mean. 68% between m+d and m-d. Therefore the distribution of everything >m+d and <m-d is 32%. The distribution less than m+d is 68% + 32%/2.