返回列表 发帖

求教 标准差!

7.51 8.22 7.86 8.36
8.09 7.83 8.30 8.01
7.73 8.25 7.96 8.53
A vending machine is designed to dispense 8 ounces of coffee into a cup. After a test that recorded the number of ounces of coffee in each of 1,000 cups dispensed by the vending machine, the 12 listed amounts , in ounces, were selected from the data. If the 1,000 recorded amounts have a mean of 8.1 ounces and a standard deviation of 0.3 ounce, how many of the 12 listed amounts are within 1.5 standard deviations of the mean?
答案有 4,6,9,10,11
正确答案是11
谢谢~
收藏 分享

统计没学好啊  麻烦各位 !
谢谢~

TOP

额 8.1+0.3*1.5到8.1-0.3*1.5
就一个不在里面呀 看一下标准差定义..

TOP

mean +- (s.d.*1.5), i.e. 8.1+0.3*1.5, 8.1-0.3*1.5, some value between 7.65 and 8.55... so there should be 11 listed amounts within those two figures..

TOP

返回列表

站长推荐 关闭


美国top10 MBA VIP申请服务

自2003年开始提供 MBA 申请服务以来,保持着90% 以上的成功率,其中Top10 MBA服务成功率更是高达95%


查看