问题
单项选择题
Which of the following statement about the following frequency distribution is FALSE（）
A. The cumulative absolute frequency of the third interval is 50.
B. The cumulative absolute frequency of the fourth interval is 30.
C. The return internals are mutually exclusive.
答案
参考答案：B
解析：
The cumulative absolute frequency of the fourth interval is 80. Which is the sum of the absolute frequencies from the first to the fourth intervals.