# Posts Tagged ‘ tutorial ’

## Web Development with R – an HD video tutorial of Jeroen Ooms talk

February 3, 2010
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Here is a HD version of a video tutorial on web development with R, a lecture that was given by Jeroen Ooms (the guy who made A web application for R’s ggplot2). This talk was given at the Bay Area UseR Group meeting on R-Powered Web Apps. You can also view the slides for his talk and view (great) examples for: stockplot, lme4, and gpplot2. Thanks...

## R Tutorial Series: Regression With Interaction Variables

January 23, 2010
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Interaction variables introduce an additional level of regression analysis by allowing researchers to explore the synergistic effects of combined predictors. This tutorial will explore how interaction models can be created in R.Tutorial Files Before we...

## R Tutorial Series: Hierarchical Linear Regression

January 15, 2010
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Regression models can become increasingly complex as more variables are included in an analysis. Furthermore, they can become exceedingly convoluted when things such as polynomials and interactions are explored. Thankfully, once the potential independe...

## Pivot tables in R

January 9, 2010
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A common data-munging operation is to compute cross tabulations of measurements by categories. SQL Server and Excel have a nice feature called pivot tables for this purpose. Here we'll figure out how to do pivot operations in R.Let's imagine an experim...

## R Tutorial Series: ANOVA Tables

January 8, 2010
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The commonly applied analysis of variance procedure, or ANOVA, is a breeze to conduct in R. This tutorial will explore how R can be used to perform ANOVA to analyze a single regression model and to compare multiple models.Tutorial FilesBefore we begin,...

## R: Memory usage statistics by variable

January 4, 2010
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Do you need a way to find out which individual variables in R consume the most memory? # create dummy variables for demonstration x <- 1:1000 y <- 1:10000 z <- 1:100000 # print aggregate memory usage statistics print(paste('R is using', mem...

## SQL group by in R

December 27, 2009
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The R statistical computing environment is awesome, but weird. How to do database operations in R is a common source of questions. The other day I was looking for an equivalent to SQL group by for R data frames. You need this to compute summary statist...

## Compare performance of machine learning classifiers in R

December 23, 2009
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This tutorial demonstrates to the R novice how to create five machine learning models for classification and compare the performance graphically with ROC curves in one chart. For a simpler introduction, start with Plot ROC curve and lift chart in R. # ...

## Plot ROC curve and lift chart in R

December 18, 2009
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This tutorial with real R code demonstrates how to create a predictive model using cforest (Breiman’s random forests) from the package party, evaluate the predictive model on a separate set of data, and then plot the performance using ROC curves ...

## Joining data frames in R

December 17, 2009
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Want to join two R data frames on a common key? Here's one way do a SQL database style join operation in R.We start with a data frame describing probes on a microarray. The key is the probe_id and the rest of the information describes the location on t...