题干

以下四个命题中:
①从匀速传递的产品生产流水线上,质检员每10分钟从中抽取一件产品进行某项指标检测,这样的抽样是分层抽样;
②两个随机变量的线性相关性越强,相关系数的绝对值越接近于1;
③在某项测量中,测量结果ξ服从正态分布N(1,σ2)(σ>0),若ξ在(0,1)内取值的概率为0.4,则ξ在(0,2)内取值的概率为0.8 ;
④对分类变量XY的随机变量k2的观测值k来说,k越小,判断“XY有关系”的把握程度越大.
其中真命题的个数为(   )

A:4

B:3

C:2

D:1

上一题 下一题 0.0难度 选择题 更新时间:2019-09-06 12:33:03

答案(点此获取答案解析)

C

同类题5

根据短文内容,选择正确的答案。

C

    A man died and was on his way to another world, either heaven (天堂) or hell (地狱). When he was halfway there, he saw a beautiful, huge palace. The owner came out and asked the man to stay and live in the palace.

    "And now I just want to eat and sleep without doing any work."The man said: "I have been working hard my whole life.

    The owner of the palace said: "If so, there is nowhere else better than here for you. There is a wealth of seafood and many other delicious foods in my palace. You can eat whatever you want without anyone stopping you. And you can rest assured (肯定的) that nothing needs to be done by you."

    "That is great! This must be heaven!" said the man. And he settled down (定居) in the palace.

    At first, the man felt very happy with a life of eating and sleeping. But gradually, he felt a bit lonely and bored.

    So he went to the owner and said: "Just eating and sleeping every day is very boring. Now I'm losing interest in this kind of life. Could you help me find a job?"

    The owner replied: "Sorry, there are no jobs here at all."

    After another few months, the man could not stand it any more and went to the owner again. "I really can't stand this kind of life any more," he said. "If you do not offer me a job, I would prefer (宁愿) to go to hell rather than (也不) live here."

    The owner of the palace smiled. "Where do you think we are now?" he said. "Heaven? We are actually (实际上) in hell!"