> With a mighty Pearson's correlation of 0.091, the data indicates that this could
> be true! If you ignore the fact that the correlation is so weak that calling it 'statistically
> insignificant' would be quite generous.
I actually came to a different conclusion than the author. Here is the way I'm thinking about the presented statistics:
1. There is 17 Kebab shops (out of 400 samples) with a google review lower than 3 stars. Let's call them "bad kebabs".
2. All those "bad kebabs" actually located within 500m from the nearest station. No kebab located in further than >500m is bad.
3. So if you've ever gotten a bad donor kebab, we can safely assume that you have purchased it from a kebab shop near a train station.
Maybe there are so many kebab eaters near a train station that a mediocre kebab offering becomes profitable?
At least here, the majority of 1-2 star reviews are actually complaining about third-party delivery services like Foodora[1].
Of course the fries will be soggy and the burger luke warm when you got a guy who had to pedal a bike for half an hour to deliver it for you. Like what did you expect?
Right, but this is selection bias. There will always exist a distance D from which all bad kebabs are located.
Unless D is provenly chosen _before_ looking at the data, this has no meaning.
One also has to take the kebab density into account.
On the contrary, if everything was within five meters, that would make the finding much more impressive.