这是一道统计学的英文数学题,因为我真的看不懂Instead of wanting to know what percent of the data falls into a particular class,we often want to know what percent falls below a certain value.To make this possible,we will compute the

Question

这是一道统计学的英文数学题,因为我真的看不懂
Instead of wanting to know what percent of the data falls into a particular class,we often want to
know what percent falls below a certain value.To make this possible,we will compute the
cumulative relative frequency for each class,which is the sum of the relative frequency of that class
and all the classes below it.
Exam Score frequency relative freq.cumulative r.f.
0-

Answer 1

proportion是比例,第一题问少于30的比例和少于90的比例,看数据就知道（90~100那里有7个,占7/200的比例）
第二题,大于等于40分的比例,大于等于70的比例
第三题不懂
第四题少于70大于等于50的比例