问题 解答题
小颖和小红两位同学在学习“概率”时,做投掷骰子(质地均匀的正方体)实验,他们共做了60次实验,实验的结果如下:
朝上的点数123456
出现的次数79682010
(1)计算“3点朝上”的频率和“5点朝上”的频率.
(2)小颖说:“根据实验,一次实验中出现5点朝上的概率最大”;小红说:“如果投掷600次,那么出现6点朝上的次数正好是100次.”小颖和小红的说法正确吗?为什么?
(3)小颖和小红各投掷一枚骰子,用列表或画树状图的方法求出两枚骰子朝上的点数之和为3的倍数的概率.
答案

(1)“3点朝上”出现的频率是

6
60
=
1
10

“5点朝上”出现的频率是

20
60
=
1
3

(2)小颖的说法是错误的.这是因为:“5点朝上”的频率最大并不能说明“5点朝上”这一事件发生的概率最大.只有当实验的次数足够大时,该事件发生的频率稳定在事件发生的概率附近;

小红的判断是错误的,因为事件发生具有随机性,故“6点朝上”的次数不一定是100次;

(3)列表如下:

小红投掷的点数小颖投掷的点数123456
1234567
2345678
3456789
45678910
567891011
6789101112
P(点数之和为3的倍数)=
12
36
=
1
3

写作题

阅读下面一则网络帖子,然后按照要求写一篇150词左右的英语短文,作为跟帖。

Hello there,

I’m writing to ask you for help. It’s really urgent because I’m considering running away from home. I feel like there's no way to fix the problem with my mother.

Yesterday evening, we had a heated argument at home after I got home a bit late again.

I had been at my friend’s birthday party. I explained it to her but she just didn’t believe me.

I do know my mother loves me very much and she wants me around every day, or even every minute.

But the fact is that I am 17 years and have my own life style. I am my parents’ only child and my mother says she wants me to have the best possible chance of happiness in the future. She is always telling me to behave well when I leave home or go out. What’s worse, whenever there is a cold war between my mother and me, my father often keeps silent. I am not only confused but also hurt. I don't know what to say or what to do to make things right. I think they are out of fashion and too old to know my inner part.

To tell the truth, I have packed up my backpack but am still at a loss.

Kate

[写作内容]

1. 以约30个词概括短文的要点;

2. 然后以约120个词就Kate遇到的困惑发表看法,并包括如下要点:

(1) 你认为Kate是否应该离家出走,为什么?

(2) 给Kate提出至少2-3点建议。

[写作要求]

可以使用实例或其它论述方法支持你的论点,也可以参照阅读材料的内容,但不得直接引用原文中的句子;

[评分标准]

概括准确,语言规范,内容合适,篇章连贯。

多项选择题