问题
解答题
测量某一距离，发生的误差X是随机的，并且从样本分析知X的方差是4，求在三次测量中至少有一次误差的绝对值超过4的概率.
答案
0.13
解：误差X是随机的正负数，是众多的、互不相干的、不分主次的偶然因素作用之和，它服从正态分布N(0,4).所以
故所求事件的概率为
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测量某一距离，发生的误差X是随机的，并且从样本分析知X的方差是4，求在三次测量中至少有一次误差的绝对值超过4的概率.
0.13
解：误差X是随机的正负数，是众多的、互不相干的、不分主次的偶然因素作用之和，它服从正态分布N(0,4).所以
故所求事件的概率为
| 完形填空。 | ||||
| Two friends 1 a picnic together. Their names are Jim and Tim. Tim is very lazy. 2 the first evening of their holiday, Jim says to Tim, "Here's some money. Go and buy some meat." "I'm too tired," 3 Tim, "You go." So Jim goes 4 the meat. 5 he comes back. He says to Tim, "Here's the meat now, please cook it." But Tim answers, "No, I'm not good at 6 , you do it," So Jim cooks it, 7 he says to Tim, "Go and 8 some water." "No, I don't want to get my clothes dirty," Tim answers. 9 Jim says, "The meal is ready, come and eat it." "Yes, I'll do that," answers Tim, "I don't like 10 'No' all the time." | ||||
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