June 2020
Beginner to intermediate
522 pages
9h 6m
Chinese
Content preview from R 语言经典实例（原书第 2 版）
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224
｜
第
9
章
的估计范围。本章中的方法可以计算总体的均值、中位数和总体比例的置信区间。
例如，9.9 节根据样本数据计算总体均值的 95％置信区间。它的区间为 97.16 <
μ
< 103.98，
这意味着总体均值
μ
在 95.16 和 103.98 之间的概率为 95％。
另请参阅
统计术语和惯例可以有所不同。本书一般遵循 Dennis Wackerly 等人的
Mathematical
Statistic with Applications
第 6 版（Duxbury 出版社）的惯例。我们还建议你阅读这本书，
以了解有关本章所描述的统计检验的更多信息。
9.1 数据的汇总
9.1.1 问题
你需要对数据有一个基本的统计汇总。
9.1.2 解决方案
函数 summary 对于向量、矩阵、因子和数据框提供了一些有用的统计汇总：
summary(vec)
#> Min. 1st Qu. Median Mean 3rd Qu. Max.
#> 0.0 0.5 1.0 1.6 1.9 33.0
9.1.3 讨论
解决方案展示了一个向量的汇总。1st Qu. 和 3rd Qu. 分别是第一个四分位数和第三
个四分位数。同时，输出还有中位数和均值，它们是十分有用的，你可以快速检测到分
布是否是偏的。例如，解决方案中的输出显示的平均值大于中位数，这表明分布可能偏
向右侧，正如你对于对数正态分布 (lognormal) 所期望的那样。
对矩阵的汇总是逐列处理的。这里我们看到的是对矩阵 mat 的汇总，其中有三列分别为
Samp1、
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.