Today the biggest book fair of the world starts again in Frankfurt, Germany. I thought this might be a good opportunity to do you some good! Springer is one of the most renowned scientific publishing companies in the world. Normally, their books are quite expensive but also in the publishing ... [Read more...]

The two most disruptive political events of the last few years are undoubtedly the Brexit referendum to leave the European Union and the election of Donald Trump. Both are commonly associated with the political consulting firm Cambridge Analytica and a technique known as Microtargeting. If you want to understand the ... [Read more...]

A few month ago I posted about market basket analysis (see Customers who bought…), in this post we will see another form of it, done with Logistic Regression, so read on… A big supermarket chain wanted to target (wink, wink) certain customer groups better. In this special case we are ... [Read more...]

It was November last year when I seriously started blogging and it is time to share with you some experiences and highlights before the summer break… so read on! The first thing that really surprised me (and still surprises me) is the popularity of my blog – and I say this ... [Read more...]

A few months ago I published a quite popular post on Clustering the Bible… one well known clustering algorithm is k-means. If you want to learn how k-means works and how to apply it in a real-world example, read on… k-means (not to be confused with k-nearest neighbours or KNN: ... [Read more...]

It can be argued that most important decisions in life are some variant of an exploitation-exploration problem. Shall I stick with my current job or look for a new one? Shall I stay with my partner or seek a new love? Shall I continue reading the book or watch the ... [Read more...]

What is the best way for me to find out whether you are rich or poor, when the only thing I know is your address? Looking at your neighbourhood! That is the big idea behind the k-nearest neighbour (or KNN) algorithm, where k stands for the number of neighbours to ... [Read more...]

The Rosetta mission of the European Space Agency (ESA) is one of the greatest (yet underappreciated) triumphs of humankind: it was launched in 2004 and landed the spacecraft Philae ten years later on a small comet, named 67P/Churyumov–Gerasimenko (for the whole timeline of the mission see here: Timeline of ... [Read more...]

You may have misread the title as the old correlation does not imply causation mantra, but the opposite is also true! If you don’t believe me, read on… First I want to provide you with some intuition on what correlation is really all about! For many people (and many ... [Read more...]

Many of you might have heard of the concept “Wisdom of the Crowd”: when many people independently guess some quantity, e.g. the number of marbles in a jar glass, the average of their guesses is often pretty accurate – even though many of the guesses are totally off. The same ... [Read more...]

One of the most notoriously difficult subjects in statistics is the concept of statistical tests. We will explain the ideas behind it step by step to give you some intuition on how to use (and misuse) it, so read on… Let us begin with some coin tosses and the question ... [Read more...]

The area of combinatorics, the art of systematic counting, is dreaded territory for many people so let us bring some light into the matter: in this post we will explain the difference between permutations and combinations, with and without repetitions, will calculate the number of possibilities and present efficient R ... [Read more...]

A few months ago I published a post on recursion: To understand Recursion you have to understand Recursion…. In this post we will see how to use recursion to fill free areas of an image with colour, the caveats of recursion and how to transform a recursive algorithm into a ... [Read more...]

There are a million reasons to learn R (see e.g. Why R for data science – and not Python?), but where to start? I present to you the ultimate introduction to bring you up to speed! So read on… I call it ultimate because it is the essence of many ... [Read more...]

Bavaria is known for its famous Oktoberfest… and within Germany also for its presumably difficult Abitur, a qualification granted by university-preparatory schools in Germany. A mandatory part for all students is maths. This year many students protested that the maths part was way too hard, they even started an online ... [Read more...]

R is one of the best choices when it comes to quantitative finance. Here we will show you how to load financial data, plot charts and give you a step-by-step template to backtest trading strategies. So, read on… We begin by just plotting a chart of the Standard & Poor’s 500 (... [Read more...]

Tomorrow, on the First of May, many countries celebrate the so called International Workers’ Day (or Labour Day): time to talk about the unequal distribution of wealth again! A few months ago I posted a piece with the title “If wealth had anything to do with intelligence…” where I argued ... [Read more...]

Like most people you will have used a search engine lately, like Google. But have you ever thought about how it manages to give you the most fitting results? How does it order the results so that the best are on top? Read on to find out! The earliest search ... [Read more...]

In this post we are talking about one of the most unintuitive results of statistics: the so called false positive paradox which is an example of the so called base rate fallacy. It describes a situation where a positive test result of a very sensitive medical test shows that you ... [Read more...]

One of the problems of navigating an autonomous car through a city is to extract robust signals in the face of all the noise that is present in the different sensors. Just taking something like an arithmetic mean of all the data points could possibly end in a catastrophe: if ... [Read more...]