How color at new red
A: Look ____ my ____ skirt.
B: ____ nice!
A: What ____ is my skirt?
B: It's ____.
A: Red? It's yellow. (黄色的)
组号
1
2
3
4
5
6
7
8
频数
10
13
x
14
15
12
9
则第3组的频率为( )
17-9=( )