Author Archives: norbert

About norbert

Biometrician at Clinical Trial Centre, Leipzig University (GER), with degrees in sociology (MA) and public health (MPH).

Sample Size Calculation Using R

Preample “Sample Size Calculation Using R” – the title of this blog post – sounds very comprehensive. However, this post only deals with the sample size collection for one particular test (two sample t-test). A collection of functions for basic … Continue reading

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How to Plot Venn Diagrams Using R, ggplot2 and ggforce

Intro Venn diagrams – named after the English logician and philosopher John Venn – “illustrate the logical relationships between two or more sets of items” with overlapping circles. In this tutorial, I'll show how to plot a three set venn … Continue reading

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How to plot GPS data using R, ggplot2 and ggmap

Intro A couple of months ago, I bought a mobile GPS navigation device. The device makes it possible to record the routes we travel with our car. Since the routes can by exported as .gpx files, it is rather easy … Continue reading

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R Markdown: How to place two tables side by side using ‘knitr’ and ‘kableExtra’

Intro When I was recently writing some report using R Markdown, I wanted to place two rather small tables side by side. Since I usually use the kable()-function of the knitr package and the kableExtra package to print tables, I … Continue reading

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Analyse der DFG Fachkollegienwahl 2015 — Teil I

Die Deutsche Forschungsgemeinschaft (DFG) ist die europaweit größte Forschungsförderungsorganisation mit einem Jahresetat von aktuell etwa 3 Milliarden Euro (2016). Die Aufgabe der DFG besteht in der Auswahl und Finanzierung wissenschaftlicher Forschungsvorhaben an Hochschulen und Forschungsinstituten. Laut DFG werden eingereichte Förderanträge … Continue reading

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How to draw a CONSORT flow diagram using R and GraphViz

Intro The acronym CONSORT stands for “Consolidated Standards of Reporting Trials”. The CONSORT statement is published by the CONSORT group and gives recommendations aiming to improve the quality of reports of randomized clinical trials. Besides a 25 item checklist, the … Continue reading

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How to Assign Variable Labels in R

Intro Defining variable labels is a useful way to describe and document datasets. Unlike SPSS, which makes it very easy to define variable labels using the data editor, base R doesn't provide any function to define variable labels (as far … Continue reading

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