Pearson vs. Spearman – some statistic basics

Friday, March 17. 2006

So I finally got to decide which test to use for my statistical analysis. Unluckily the lecture I took about statistics was in 1999… So I got to research on certain issues now again. But the web is quite a good place to get answers for certain questions, so I see that Pearson vs. Spearman is a quite common issue, So it didn’t take me long to finde some sources to solve my problem:

„The Pearson and Spearman's coefficients are mathematically identical, EXCEPT that the Spearman rank coefficient is calculated from the ranks of each variable, not the actual values. Once the values are ranked, they both use the same formula.” Source.

„Bei intervallskalierten und normalverteilten Proben wird die Produkt-Moment-Korrelation nach Pearson, bei ordinalskalierten und nicht normalverteilten Proben die Rangkorrelation nach Spearman verwendet, welche die Ränge der untersuchten Daten miteinander vergleicht (Bühl & Zöfel 1995, Sachs 1993). Letzteres Verfahren gilt zudem als robuster gegenüber Ausreißern (Sachs 1993). Precht und Kraft (1992) sowie Bühl und Zöfel (1995) weisen darauf hin, dass eine Korrelationsanalyse nur dann sinnvoll ist, wenn der Zusammenhang linear ist; für U-förmige Zusammenhänge tendiert r gegen 0.“ Source.

So it should be better to use Spearman for me, because a) I don’t have to justify why my data should be normally distributed and b) some of the values are not really metrically scaled.

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Progress! ...finally

Monday, March 13. 2006

Seems like the efforts I’m putting into my business teaching exam are finally successful. My concept for this exam is almost done. Although there are some spots to improve on, I’m quite confident that my preparation will at least be sufficient to pass.

The topic I specialised in is “media diversity at the vocational education – chances and risks” under this very broad topic I took out one perspective of media diversity. This covers all kind of internet / e-learning technologies, which might be interesting for education. But since it is also a really big topic to discuss how these technologies can or cannot improve education I will further put my focus on efficient usage of those technologies in classes. For this usage a necessity for hybrid/complex teaching and learning environment can be seen. How coincidental the concept of “Selforganized Learning” fits here!

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What is "media diversity"?

Sunday, March 12. 2006

Guess I’ll need that for my exam on Wednesday - at least as a snippet. So I use this topic to break the series of “useless” tagged entries… First there are two perspectives on this topic on is more macro-economical and quantitative, and considers the different available media offerings in a country e.g. the topic that German Publishing giant Springer (who among other things publishes “Bild” – Germany’s most read tabloid) was not allowed to take over the private TV broadcaster ProSiebenSat.1. So if there would only be one or two big companies running all the media in a country you could consider the media diversity as very shallow.

The other approach towards media diversity is more micro-economical and qualitative. This is more the perspective I want to use when I’m writing about media diversity related to teaching. Here you can consider it as the “use of different tools, media types and materials”. So in this context we might just consider it as many different media channels, which are used. Talking about inevitably the various possibilities of the internet may strike us. It can’t be regarded as one media channel, but has to be analyzed more deeply to get an overview over the different channels there.

Further thoughts on this topic are appreciated!

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I don’t want to find my spare battery – I want chocolate!

Wednesday, January 25. 2006

This posting matches the meaningless Blogs and Wikis my friends have opened recently (here is a meaningless video of yesterdays frozen beer btw.). I’m right now sitting in the Wirtschaftspädagogik Examenscolloquium, which is an obligatory seminar if you want to take part in the exam. Right now I feel the urgent need for some sweets – but unluckily all the chocolate I carried around in my bag is gone. The only thing I could retrieve out of the depths of my bag was the spare battery for my mobile (for which I was searching for quite a while). Through a flash of inspiration I searched my jacket, and found at least some cough drops. Those are now getting consumed by Bine and me. The sugar of the sweets keeps our mood on a bearable level, but the green background (see picture on the left) of Dennis’ charts is about to drive me insane. So I’m hoping that he’ll finish his presentation soon – although the discussion is really interesting. Why is such a minor issue distracting me that much?

Anyway - lessons learned today:

  • Those mobile phones guarantee entertainment
  • Never leave the house without chocolate
  • Brief your fellow students with current ergonomic powerpoint design schemes

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