1557 search results for "regression"

Another bunch of R (and JAGS) scripts

August 31, 2012
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Another bunch of R (and JAGS) scripts

Probably sooner than I expected, I have managed to also upload the codes for the examples in Chapter 5 of the book, which deals with doing Bayesian health economic evaluations. Basically, there are 3 examples, which sort of represent the main clas...

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PCA or Polluting your Clever Analysis

August 31, 2012
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PCA or Polluting your Clever Analysis

When I learned about principal component analysis (PCA), I thought it would be really useful in big data analysis, but that's not true if you want to do prediction. I tried PCA in my first competition at kaggle, but it delivered bad results. This post illustrates how PCA can pollute good predictors.When I started examining this problem,...

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Processing Data from a Statistica Worksheet Using R

August 29, 2012
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Processing Data from a Statistica Worksheet Using R

Context: I work with data from non-profit organizations, and so a big concern in many of my analyses is if and how much people are donating from one year to the next.  One of the  things I normally like to do … Continue reading →

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Integrating R into a SAS shop

August 29, 2012
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I work in an environment dominated by SAS, and I am looking to integrate R into our environment. Why would I want to do such a thing? First, I do not want to get rid of SAS. That would not only take away most of our investment in SAS training and hiring good quality SAS programmers, but...

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Facts About R Packages (1)

August 29, 2012
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R Packages growth Curve Why R is so popular? There are a lot of reasons, such as: easy to learn and convenient to use, active community, open source, etc. Another important reason is the numerous contributed packages. Up to yesterday, there are 4033 R...

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Generate Quasi-Poisson Distribution Random Variable

August 29, 2012
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Most of regression methods assume that response variables follow some exponential distribution families, e.g. Guassian, Poisson, Gamma, etc. However, this assumption was frequently violated in real world by, for example, zero-inflated overdispersion problem. A number of methods were developed to deal with such problem, and among them, Quasi-Poisson and Negative Binomial are the most popular methods perhaps due to that...

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Newton-Raphson can compute an average

August 28, 2012
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Newton-Raphson can compute an average

In our article How robust is logistic regression? we pointed out some basic yet deep limitations of the traditional full-step Newton-Raphson or Iteratively Reweighted Least Squares methods of solving logistic regression problems (such as in R‘s standard glm() implementation). In fact in the comments we exhibit a well posed data fitting problem that can not Related posts:

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Structural Equation Modeling: Separating the General from the Specific (Part II)

August 26, 2012
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Structural Equation Modeling: Separating the General from the Specific (Part II)

As promised in Halo Effects and Multicollinearity (my last post), I will show how to run a confirmatory factor analysis in R to test our bifactor model.  In addition, I will include a dependent variable and fit a structural equation mode...

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Why R for Mass Spectrometrist and Computational Proteomics

August 25, 2012
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Why R for Mass Spectrometrist and Computational Proteomics

Why R:Actually, It is a common practice the integration of the statistical analysis of the resulted data and in silico predictions of the data generated in your manuscript and your daily research. Mass spectrometrist, biologist and bioinformaticians c...

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Exporting ctree object to Asymptote

August 25, 2012
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Exporting ctree object to Asymptote

When producing regression or classification trees (standard rpart or ctree from party package) in GNU R I am often unsatisfied with the default plots they produce. One of many possible solutions is to export a tree plot to Asymptote.The ...

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