一个容量100的样本，其数据的分组与各组的频数如表
|
由表格知，样本事件落在（10，20]上的频率是
=0.13，13 100
样本事件落在（20，30]上的频率是
=0.24，24 100
样本事件落在（30，40]上的频率是
=0.15，15 100
落在三个区间上是互斥的，
根据互斥事件的概率得到样本事件落在（10，40]上的频率是0.13+0.24+0.15=0.52
故答案为：0.52
| 根据对话内容选项恰当的句子，有两项为多余的。 | |
B: Sorry, I don't have one. A: So I must go to the shop near our school. B: I think the shop is closed at this time of day. A: 2_____. B: It's Friday. On Friday the shop closes early. A: 3_____? B: Look, it says "closed". A: Oh, dear! you're right. It is closed. 4_____? B: 5_____. It's open 24 hours. A: OK, Let's go. |