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IMAGINE, THINK, and DO
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Local Notes

Local Notes 是一款 Windows 下的笔记系统.

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Sowya 是一款运行于 Windows 下的计算软件.

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注: 自 v0.550 开始, Calculator 更名为 Sowya. [Sowya] 是吴语中数学的发音, 可在 cn.bing.com/translator 中输入 Sowya, 听其英语发音或法语发音.





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Problèmes d'affichage aléatoires

概率统计 >> 概率论
Questions in category: 概率论 (Probability).

[Exer9-4] Exercise 7 of Book {Devore2017B} P.149

Posted by haifeng on 2020-04-14 08:22:05 last update 2020-04-15 22:43:53 | Answers (1)


The time $X$ (min) for a lab assistant to prepare the equipment for a certain experiment is believed to have a uniform distribution with $A=25$ and $B=35$.

  • (a) Write the pdf of $X$ and sketch its graph.
  • (b) What is the probability that preparation time exceeds $33$ min?
  • (c) What is the probability that preparation time is within $2$ min of the mean time? [Hint: Identify $\mu$ from the graph of $f(x)$.]
  • (d) For any $a$ such that $25 < a < a+2 < 35$, what is the probability that preparation time is between $a$ and $a+2$ min?