I haven’t used interaction terms in (generalized) linear model quite often yet. However, recently I have had some situations where I tried to compute regression models with interaction terms and was wondering how to interprete the results. Just looking at the estimates won’t help much in such cases. ... [Read more...]

We often use logistic regression models in our analyses and we also often need to publish the results in table format. And, we always use MS Word since this is our standard office in our department. So I thought about … Weiterlesen → [Read more...]

First of all, credits for this script must go to Ethan Brown, whose ideas for creating Likert scales like plots with ggplot built the core of my sjPlotLikert.R-script. All I did was some visual tweaking like having positive percentage values … Weiterlesen → [Read more...]

This script was almost written on parallel to the sjPlotCorr script because it uses a very similar ggplot-base. However, there’s also a very nice posting over at Martin’s Bio Blog which show alternative approaches on plotting PCAs. Anyway, if you … Weiterlesen → [Read more...]

This week I read the book by Michael Chernick and Robert LaBudde, An Introduction to Bootstrap Methods with Applications to R. It’s an interesting oeuvre for useRs of all stripes. I strongly recommend check it out. The book brings lots of examples of bootstrapping applications, such as standard errors, ... [Read more...]

Polygon is a such handy function in R for drawing beautiful charts where we can select regions (polygons) of the surface. It’s quite useful for indicating confidence regions of parameters, predictions for time-series, or areas under distributions: [Read more...]

Most computers nowadays have few cores that incredibly help us with our daily computing duties. However, when statistical softwares do use parallelization for analyzing data faster? R, my preferred analytical package, does not take too much advantage of multicore processing by default. In fact, R has been inherently a “single-processor” ... [Read more...]

Sometimes people ask me how the examples of my plotting functions I show here can be reproduced without having a SPSS data set (or at least, without having the data set I use because it’s not public yet). So I … Weiterlesen → [Read more...]

I sometimes get questions on how to reproduce the samples that are posted in this blog. Currently, I’m referring to these posts: Plotting lm and glm models with ggplot Easily plotting grouped bars with ggplot Simplify frequency plots with ggplot … Weiterlesen → [Read more...]

Update I followed the advice from Tim’s comment and changed the scaling in the sjPlotOdds-function to logarithmic scaling. The screenshots below showing the plotted glm’s have been updated. Summary In this posting I will show how to plot results from … Weiterlesen → [Read more...]

A colleague asked me for how one can change axis attributes in a basic plot. Plotting anything in R is really, really easy. It is enough typing plot(x, y). In general, plot functions are nicely pre-cooked, so hardly one needs to change anything. But if changes in the default ... [Read more...]

Summary This tutorial shows how to create diagrams with grouped bar charts or dot plots with ggplot. The groups can also be displayed as facet grids. Importing the data from SPSS All following examples are based on an imported SPSS … Weiterlesen → [Read more...]

The Times Higher Education (http://www.timeshighereducation.co.uk) released its World Reputation Ranking. The ranking employs survey consultation among invited-only academics to measure reputation among several universities. It is assumed to be the world’s largest opinion survey of this sort across the globe. Every year, a list of ... [Read more...]

Update March 5th All downloads are now accessible from my script page! Summary This posting shows how to plot frequency plots using the ggplot-package in R. Compared to SPSS standard outputs, you will learn how to create appealing diagrams ready … Weiterlesen → [Read more...]

Update/ Thanks to Bernd I could improve the function of how to import the data, so here’s the updated script! /Update In R, you often may have scripts or code snippets that will be reused. In such cases, you can … Weiterlesen → [Read more...]

Preface I will every now and then post my experience with R, a package for statistical analyses. I try to show some solutions for common types of analyses or problems you are facing when you start working with R. These … Weiterlesen → [Read more...]

Far as I remember, today was the first day in my life I succeed to load a text file bigger than 1.5 Gb into R (~ 5 million lines and 18 columns). My computer is not a small stuff, I’m using a Macbook Pro with rough 8GB of RAM, but the issue why ... [Read more...]

Since we are in the “big data” Era, which means that a massive amount of data are made daily available by governments, institutions, and ordinary people like you and me—the importance of simulate data for “frequentists”, like myself, seems to fade. After all, once we have access to “real ... [Read more...]

Most statistical softwares nowadays are able to convert their files to a wide range of other packages. Perhaps it is the reason for the discontinuity of old converter bundles like SAS Transport and DBMS. Interesting, however, Stata, a quite popular statistical package, still lack built-in support for exporting and importing ... [Read more...]

I’ve friends favouring Stata rather than R, while others do the inverse. However, few of them actually know that it is possible to work on both softwares, simultaneously inclusive. It is possible to integrate R and Stata, complementing so we can run almost all kind of analyses using them. ... [Read more...]