Thursday, February 19, 2009

Statistical Modeling, Causal Inference, Social Science, and … where is my Comment?

Here is what Andrew Gelman posted on his blog:

I have never ever seen an example where I’ve felt a boxplot was appropriate. I’m open to being convinced, but I don’t think you’ll be able to convince me. Bring on the examples!

You can imagine that I can’t really agree with him, and I guess that the Tour de France examples posted on this blog are at least one counterexample showing the flexibility and usefulness of boxplots. There are certainly some drawbacks of the design (symmetric whiskers, very large data, …) but over all, boxplots are as simple as versatile - who would dare to ignore this.

Feel free to comment, I promis, I won’t censor your comments … 
Posted by Martin at 20:35:27 | Permalink | Comments (1) »

Monday, February 16, 2009

Another Trivial Plot

Like all nations who fight the global financial and economic crises, Germany has put a package over several hundred billion euros. One part of the package is the so called “Umweltprämie”, which is nothing else than a voucher over 2,500 euros for everybody who turns in his/her 9 or more years old car to be trashed and buys a new car.

Although we can assume the number of nine or more year old cars to be finite, there is a limit on the number of vouchers, which is set to 600,000. Now we come to the trivial plot. The simple pie chart shows the proportion of voucher given out so far.

I did start to record the numbers last week, and with a week worth of data the increase looks like this:
So far we seem to be still far away from the limit of 600,00. A simple linear regression yields this graph, and a results that tells us that the vouchers will be used up even before summer at May 31st:
The linear estimate is certainly not a very fancy prediction here … 

When we have something around three weeks of data, I will post the data and open up the round for the best prediction - stay tuned!
Posted by Martin at 19:46:01 | Permalink | Comments (2)

Monday, February 2, 2009

Put him to the test …

At www.politifact.com they put up the Obameter - the ultimate chart, which shows the progress of president Obama’s work.

So far just a simple barchart, but it has the potential for a timeseries chart, which shows Obama’s success - or failure - over time.
Posted by Martin at 17:51:20 | Permalink | Comments (2)