# Blog Archives

## Summarize Missing Data for all Variables in a Data Frame in R

February 16, 2011
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Something like this probably already exists in an R package somewhere out there, but I needed a function to summarize how much missing data I have in each variable of a data frame in R. Pass a data frame to this function and for each variable it'll give you the number of missing values, the total N, and the...

## Summarize Missing Data for all Variables in a Data Frame in R

February 16, 2011
By

Something like this probably already exists in an R package somewhere out there, but I needed a function to summarize how much missing data I have in each variable of a data frame in R. Pass a data frame to this function and for each variable it'll give you the number of missing values, the total N, and the...

## R function for extracting F-test P-value from linear model object

January 10, 2011
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I thought it would be trivial to extract the p-value on the F-test of a linear regression model (testing the null hypothesis R²=0). If I fit the linear model: fit<-lm(y~x1+x2), I can't seem to find it in names(fit) or summary(fit). But summary(fit)\$fstatistic does give you the F statistic, and both degrees of freedom, so I wrote this function to...

## Webinar on Revolution R Enterprise

December 7, 2010
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R evangelist David Smith, marketing VP at Revolution R, will be giving a webinar showing off some of the finer features of Revolution R Enterprise - an integrated development environment (IDE) for R that has an enhanced script editor with syntax highli...

## Using the "Divide by 4 Rule" to Interpret Logistic Regression Coefficients

December 6, 2010
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I was recently reading a bit about logistic regression in a book on hierarchical/multilevel modeling when I first learned about the "divide by 4 rule" for quickly interpreting coefficients in a logistic regression model in terms of the predicted probabilities of the outcome. The idea is pretty simple. The logistic curve (predicted probabilities) is steepest at the center where...

## Syntax Highlighting R Code, Revisited

November 17, 2010
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A few months ago I showed you how to syntax-highlight R code using Github Gists for displaying R code on your blog or other online medium. The idea's really simple if you use blogger - head over to gist.github.com, paste in your R code, create a public "gist", hit "embed", then copy the javascript onto your blog. However, if...

## Install and load R package "Rcmdr" to quickly install lots of other packages

September 21, 2010
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I recently reformatted my laptop and needed to reinstall R and all the packages that I regularly use. In a previous post I covered R Commander, a nice GUI for R that includes a decent data editor and menus for graphics and basic statistical analysis. Since Rcmdr depends on many other packages, installing and loading Rcmdr like this... install.packages("Rcmdr", dependencies=TRUE)library(Rcmdr) ..

## Embed R Code with Syntax Highlighting on your Blog

September 7, 2010
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If you use blogger or even wordpress you've probably found that it's complicated to post code snippets with spacing preserved and syntax highlighting (especially for R code). I've discovered a few workarounds that involve hacking the blogger HTML templ...

August 31, 2010
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A few weeks ago I suddenly reached the point that every graduate student once thought would never come - time to start writing my thesis. With a blank page and a blinking cursor staring me in the face it's time to compile all of my published and unpubl...

## Deducer: R and ggplot2 GUI

August 16, 2010
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Last Year I introduced you to R Commander, a nice graphical user interface (GUI) for R for those of you who are still hesitant to leave the clicky-box style research a la SPSS for the far more superior reproducible research using R. As most of you know...