作业帮奇怪,一道英文的数学方差问题,怎么不对啊!
来源：学生作业帮 编辑：作业帮 分类：英语作业 时间：2024/05/26 02:48:19
奇怪,一道英文的数学方差问题,怎么不对啊!
The ages of students in a class have been put into the frequency
distribution below.
Age Number of Students
18 3
19 5
20 28
21 4
What is the standard deviation for this
(population) set of data?
选项是：
a.1.12
b.0.703
c.1.35
d.1.25
e.0.494
平均数是19.然后我得到1.5^2x7+0.25x33 的和除以40，得到0.再加根号！
The ages of students in a class have been put into the frequency
distribution below.
Age Number of Students
18 3
19 5
20 28
21 4
What is the standard deviation for this
(population) set of data?
选项是：
a.1.12
b.0.703
c.1.35
d.1.25
e.0.494
平均数是19.然后我得到1.5^2x7+0.25x33 的和除以40，得到0.再加根号！
平均数是19.825 ,方差0.703,选