Abstract: We introduce the R package socialroulette, which is a lightweight package for handling the recurrent problem of assigning individuals into groups of a fixed size. In order to minimize reunions, we provide an algorithm to solve the task as an ... [Read more...]

Abstract: When distributing individuals into groups every week for a virtual social mixer, e.g. using Zoom breakout rooms, it’s boring to end up in a group with someone, who you already met last week. We compute the probility for this to happen and state a simple rejection sampling ... [Read more...]

Abstract: This page is an updated version of the 2020-12-28 blog post Age Stratified All-Cause and COVID-19 Associated Mortality. The post considers the age stratified all-cause and COVID-19 associated mortality in Germany during 2020 based on numbers ... [Read more...]

Abstract: We consider the age stratified all-cause and COVID-19 associated mortality in Germany during 2020 based on numbers provided by the Federal Statistical Office and the Robert Koch Institute. This work is licensed under a Creative Commons A... [Read more...]

Abstract: Slides, R code and video lectures of our 2020 The Mathematics and Statistics of Infectious Disease Outbreaks summer course at Stockholm University are made available to a wider audience. This work is licensed under a Creative Commons At... [Read more...]

Abstract: We attempt a mathematical description of the risk scoring algorithm used in the Google and Apple exposure notification framework (v1). This algorithm is used in many digital contact tracing apps for COVID-19, e.g., in Germany or Switzerland. ... [Read more...]

Abstract: We look at superspreading in infectious disease transmission from a statistical point of view. We characterise heterogeneity in the offspring distribution by the Gini coefficient instead of the usual dispersion parameter of the negative binomial distribution. This allows us to consider more flexible offspring distributions. This work is licensed ... [Read more...]

Abstract: We discuss the estimation with R of the time-varying effective reproduction number during an infectious disease outbreak such as the COVID-19 outbreak. Using a single simulated outbreak we compare the performance of three different estimation methods. This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. The markdown+... [Read more...]

Abstract: We discuss why the message of flattening the COVID-19 curve is right, but why some of the visualizations used to show the effect are wrong: Reducing the basic reproduction number does not just stretch the outbreak, it also reduces the final size of the outbreak. This work is licensed ... [Read more...]

Abstract: Web-scraped data are used to put a Rubik’s cube competition result into perspective. The sugarcoating consists of altering the sampling frame of the comparison to the more relevant population of senior first time cubers. This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. The markdown+Rknitr ... [Read more...]

Abstract: We use the RMariaDB and dbplyr packages to analyze the results database of the World Cubing Association. In particular we are interested in finding unofficial world records of fastest 3x3x3 solves, countries with large proportion of female cubers as well as acceptable solving times before entering a WCA ... [Read more...]

Abstract: The perfect circle is a shiny app providing a user friendly interface to the algorithm described in the previous blog post Judging Freehand Circle Drawing Competitions. The app allows one to score freehand circles directly from the mobile by uploading photos of them them to a shiny server. An ... [Read more...]

Abstract: We use the purrr package to solve a popular math puzzle via a combinatorial functional programming approach. A small shiny app is provided to allow the user to solve their own variations of the puzzle. This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. The markdown+Rknitr ... [Read more...]

Abstract: As an applied statistician you get in touch with many challenging problems in need of a statistical solution. Often, your client/colleague already has a working solution and just wants to clarify a small statistical detail with you. Equally o... [Read more...]

Abstract: In 2007 Alexander Overwijk went viral with his 'Perfect Circle' video. The same year a World Freehand Circle Drawing Championship was organized, which he won. In this post we show how a mobile camera, R and the imager package can be used to develop an image analysis based method to ... [Read more...]

Abstract: In this post we use R's capabilities to solve nonlinear equation systems in order to answer an extension of the hanging cable problem to suspension bridges. We then use R and ggplot to overlay the solution to an image of the Golden Gate Bridge in order to bring together ... [Read more...]

Abstract: We follow up on last weeks post on using Gapminder data to study the world's income distribution. In order to assess the inequality of the distribution we compute the Gini coefficient for the world's income distribution by Monte Carlo approximation and visualize the result as a time series. Furthermore, ... [Read more...]

Abstract: We work out the math behind the so called income mountain plots used in the book "Factfulness" by Hans Rosling and use these insight to generate such plots using tidyverse code. The trip includes a mixture of log-normals, the density transformation theorem, histogram vs. density and then skipping all ... [Read more...]

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