## Teach R to read handwritten Digits with just 4 Lines of Code

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 neighbours (or KNN) algorithm, where k stands for the number of neighbours to look at. The idea couldn’t be any simpler yet the results are often very impressive indeed – so read on…
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## Creating a Movie with Data from Outer Space in R

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 Rosetta spacecraft).

ESA provided the world with datasets of the comet which we will use to create an animated gif in R… so read on!
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## Understanding AdaBoost – or how to turn Weakness into Strength

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 principle is at work in so-called ensemble methods, like bagging and boosting. If you want to know more about boosting and how to turn pseudocode of a scientific paper into valid R code read on…
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## From Coin Tosses to p-Hacking: Make Statistics Significant Again!

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…
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## Learning R: Permutations and Combinations with Base R

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 (also called replacements), will calculate the number of possibilities and present efficient R code to enumerate all of them, so read on…
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## Learning R: Painting with Fire

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 loop-based version using a queue – so read on…
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## Learning R: The Ultimate Introduction (incl. Machine Learning!)

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…
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## Was the Bavarian Abitur too hard this time?

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 petition with more than seventy thousand supporters at this time of writing!

It is not clear yet whether their marks will be adjusted upwards, the ministry of education is investigating the case. As a professor in Bavaria who also teaches statistics I will take the opportunity to share with you an actual question from the original examination with solution, so read on…
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## Backtest Trading Strategies Like a Real Quant

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…