02 2015 档案
摘要:This is to continue on the topic of using themelt/castfunctions inreshapeto convert between long and wide format of data frame. Here is the example I ...
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摘要:导语活动做不好会伤用户,伤产品。很多人以为活动能让产品收入突飞猛进,很多人以为活动能弥补产品的缺陷。其实活动不是解决方案,只是止痛药。他解决不了根本的问题,只能减少疼痛而已。而有时候,药方子开错了,会让伤口更疼!所以有时候不做活动反而更好!┃七宗罪之一:给太多奖励给少了,玩家会骂你抠门。奖励给多了,...
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摘要:Statistical approaches to randomised controlled trial analysisThe statistical approach used in the design and analysis of the vast majority of clinica...
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摘要:Today is a good day to start parallelizing your code. I’ve been using the parallel package since its integration with R (v. 2.14.0) and its much easie...
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摘要:From original post @http://analyticsblog.mecglobal.it/analytics-tools/bashr/In the world of data analysis, the term automation runs hand in hand with ...
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摘要:dplyr 0.4.0January 9, 2015 inUncategorizedI’m very pleased to announce that dplyr 0.4.0 is now available from CRAN. Get the latest version by running:...
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摘要:关于分类算法我们之前也讨论过了KNN、决策树、naivebayes、SVM、ANN、logistic回归。关于这么多的分类算法,我们自然需要考虑谁的表现更加的优秀。 既然要对分类算法进行评价,那么我们自然得有评价依据。到目前为止,我们讨论分类的有效性都是基于分类成功率来说的,但是这个指标科学吗...
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摘要:This post builds on aprevious post, but can be read and understood independently.As part of my course on statistical learning, we created 3D graphics ...
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摘要:1、余弦距离余弦距离,也称为余弦相似度,是用向量空间中两个向量夹角的余弦值作为衡量两个个体间差异的大小的度量。向量,是多维空间中有方向的线段,如果两个向量的方向一致,即夹角接近零,那么这两个向量就相近。而要确定两个向量方向是否一致,这就要用到余弦定理计算向量的夹角。余弦定理描述了三角形中任何一个夹角...
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摘要:(1)C4.5算法的特点为:输入变量(自变量):为分类型变量或连续型变量。输出变量(目标变量):为分类型变量。连续变量处理:N等分离散化。树分枝类型:多分枝。分裂指标:信息增益比率gain ratio(分裂后的目标变量取值变异较小,纯度高)前剪枝:叶节点数是否小于某一阈值。后剪枝:使用置信度法和减少...
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摘要:Joanna Zhao’s and Jenny Bryan’sR graph catalogis meant to be a complement to the physical book,Creating More Effective Graphs, but it’s a really nice ...
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摘要:In preparation for a R Workgroup meeting, I started thinking about what would be my "Top 5 R Functions". I ruled out the functions for basic mechanics...
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摘要:This slidify-based deck introduces the shinypackage from R-Studio and walks one through the development of an interactive application that presents us...
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摘要:Usually when I create slide decks these days I used markdown and slidy. However, I recently was asked to present using an existingRevolutionMicrosoft ...
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摘要:It has been possible for some years to launch a web map from within R. A number of packages for doing this are available, including:RgoogleMaps, an in...
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摘要:This semester I'm teaching from Hastie, Tibshirani, and Friedman's book,The Elements of Statistical Learning, 2nd Edition. The authors provide aMixtur...
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摘要:A Bayes factor (BF) is a statistical index that quantifies the evidence for a hypothesis, compared to an alternative hypothesis (for introductions to ...
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