It can be argued that the 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 movie instead? In all of those cases, the question is always whether I should “exploit” the thing I have or whether I should “explore” new things. If you want to learn how to tackle this most basic trade-off read on…

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# Author: Learning Machines

## 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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## Causation doesn’t imply Correlation *either*

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…

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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*, 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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