1825 search results for "ggplot2"

Visualizing Missing Data

March 22, 2011
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Visualizing Missing Data

There are several graphics available for visualizing missing data. The following graphic was inspired by many sources. However, I wanted a version using ggplot2. What is visualized here is the percent missing for each variable in the PISA data across countries. The code will be available as part of the multilevelPSA package I am currently

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Correlation network

March 22, 2011
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Correlation network

I came up with an idea to draw correlation network to get a grasp about relationship between a list of stocks. An alternative way to show correlation matrix would be head map, which can have limitations with big matrices (>100). Unfortunately,  ggplot2 package doesn’t have a easy way to draw the networks, so I was left

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Machine Learning Ex2 – Linear Regression

March 22, 2011
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Machine Learning Ex2 – Linear Regression

Thanks to this post, I found OpenClassroom. In addition, thanks to Andrew Ng and his lectures, I took my first course in machine learning. These videos are quite easy to follow. Exercise 2 requires implementing gradient descent algorithm to model data with linear regression. Read More: 243 Words Totally

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A 3D Version of R’s curve() Function

March 21, 2011
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A 3D Version of R’s curve() Function

I like exploring the behavior of functions of a single variable using the curve() function in R. One thing that seems to be missing from R’s base functions is a tool for exploring functions of two variables. I asked for examples of such a function on Twitter today and didn’t get any answers, so I

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How to: Binomial regression models in R

March 19, 2011
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How to: Binomial regression models in R

Ever wondered how to predict success or failure as a function of other variables? Here's a quick tutorial on binomial regression in R.

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The housing bubble by city

March 17, 2011
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The housing bubble by city

The housing bubble by city. Miami sailed high and fell far. Detroit rose modestly and but dropped more than it went up. Dallas held steady. DC is enjoying a bit of renewed growth, but are in and New York yet to fall?

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Global Migration Maps

March 17, 2011
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Global Migration Maps

 Migrations of people have existed for millennia and oc

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sab-R-metrics: Brief Sidetrack for Scatterplot Matrices

March 16, 2011
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sab-R-metrics: Brief Sidetrack for Scatterplot Matrices

In my last two posts I talked about Ordinary Least Squares, then extended this discussion to the multiple predictor case and briefly talked about some of the problems that may arise. These problems can include omitted variable bias, heteroskedasticity, non-normality, and multicollinearity. Most of these problems are relatively minor in practice and have easy fixes,...

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sab-R-metrics: Brief Sidetrack for Scatterplot Matrices

March 16, 2011
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sab-R-metrics: Brief Sidetrack for Scatterplot Matrices

In my last two posts I talked about Ordinary Least Squares, then extended this discussion to the multiple predictor case and briefly talked about some of the problems that may arise. These problems can include omitted variable bias, heteroskedasticity, non-normality, and multicollinearity. Most of these problems are relatively minor in practice and have easy fixes,...

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Visualizing Growth of a Retail Chain

March 15, 2011
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Visualizing Growth of a Retail Chain

I am a regular reader of the FlowingData blog by Nathan Yau. It is an excellent reference for anyone interested in statistical visualization of data. One of his posts that caught my attention was a visualization of the growth of Walmart in the US. Given my research interests in retail, it was a fascinating insight

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