求G友帮忙讲道数学题。。

SharonZ0902

这是做prep遇到的，连题都不大看得懂。。求大家帮忙翻译一下最后一句，给我讲讲这道题吧！
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 1000 cups dispensed by the vending machine, the 12listed amounts, in ounces, were selected from the data. If the 1000 recorded amounts have a mean of 8.1 ounces and a standard deviation of 0.3 ounce, how many of the 12listed amounts are within 1.5 standard deviations of the mean.
7.51  8.22  7.86  8.36
8.09  9.83  8.30  8.01
7.73  8.25  7.96  8.53
答案选项分别是4，6,9,10,11

谢谢！！！

Charlotte0512

a standard deviation是0.3，所以1.5 standard deviations 是1.5*0.3是0.45，和有平均数8.1差0.45以内的数在这些数中有10个

SharonZ0902

太感谢了。。。

shell6688

11个好不

bjxiaobei

数清楚好不