问题
单项选择题
Use the results from the following survey of 500 firms to answer the question.
A．Number of Employees
B．Frequency
C．300 up to 400
D．40
E．400 up to 500
F．62
G．500 up to 600
H．78
I．600 up to 700
J．101
K．700 up to 800
L．131
M．800 up to 900
N．88
答案
参考答案：B
解析：The third class is 500-600 with a frequency of 78.