Luis is a nerd ...

Luis is a nerd and so am I.

The Free-Riders II

As a second part of the previous post, this is the graph of the group contributions and the earnings per period. It is not one of my favorite graphs.


(Click on the image to see larger version)

The Free-Riders

(Click on the image to see larger version)

Tonight in class we did the classical voluntary contributions experiment. The class was divided into 5 teams. Each team had at the beginning of each period 100 tokens. At each period, the teams had to decide independently the amount of tokens to keep for private consumption and the rest of the tokens for the group contribution. Once each team decided how to split the 100 tokens, I collected the group contributions and wrote on the board the sum of those contributions (the teams did not know the amount of contributions from the other teams, just the total). Then each calculated their earnings in that period: earnings=private consumption + 0.7 (total group contribution). The factor 0.7 was arbitrarily chosen and fixed for all teams and all periods. This was repeated 10 times (with 2 periods of training at the beginning). At the very end, each time added up the earnings from each period, this total amount of earnings is the number that is at the right of the graph for each team.

The name of the winning team (notice that there was a team that chose the name "Winners" and they did not win) was switched by me to "The Free-Riders" for obvious reasons.

Notice that the winning team played the optimal strategy from the beginning. No communication was allowed in the experiment between teams, only within the teams.

This is a sample of the sheet each team had,

period	endowment	private exchange*	group exchange*	total group contribution	earnings**
1	100

*These columns must satisfy
Private Exchange + Group Exchange = 100

**To calculate this column use
Earnings = Private Exchange + 0.7 (Total Group Contribution)

Excel Question

I had to do this graph in MatLab since I could not figure out how to do it in Excel.

(Click on the image to see larger version)

Does someone know how to do the same in Excel?

(that is, how to label the dots with another series of data?)

Mario and María

Hace poco busqué en Wolfram|Alpha mi nombre y para hacer las cosas más interesantes también el de María.

Estos son los resultados.

Mario ocupa el lugar 185 de los nombres más comunes en Estados Unidos (el 0.099% de la población en este país se llama Mario). María es el lugar 64.

María ha sido un nombre más popular en Estados Unidos desde antes que Mario empezara a ser un nombre común aquí. En los años 60 María se volvió mucho más popular y ahora se está haciendo cada vez menos común.

La distribución por edades es más o menos la misma. En particular, en la población entre 35 y 40 años de edad, la proporción de gente llamada Mario es la misma que la de gente llamada María.

Wolfram|Alpha

A few years ago I used Mathematica as an easy way to graph functions and simplify expressions. Then I became fan of MatLab and now I do almost everything there. However, Wolfram (the company that sells Mathematica) has a sort of encyclopedia of math stuff that is pretty good.

But now Wolfram created a new website that is a quick resource of data and a computational tool. The website is Wolfram|Alpha.

To illustrate what it can do I will show some examples.

• For those of you that are very visual, you can type exp(sin(x+y+x*y)) and you will get among other things, the contour plot and a 3D graph of that function.
  
• For those of you that are just bored and do not feel like google it, you can type Morelia and you will get some numbers about the city.
• For those of you who are more like labs and chemistry you can try for example, benzene and then you will get a bunch of numbers and diagrams that I do not understand.
• I typed B minor and I got the structure of that scale and you can even play how it sounds.
  

Go and visit Wolfram|Alpha now and play with it. Let me know if you find cool stuff.

\pi

Parece que alguien estaba obsesionado con \pi y lo escribió en el cemento fresco de una banqueta, cual declaración de amor a una chica.

Wave

Uso muchas de las aplicaciones de Google, la que más utilizo y la que creo es la mejor es por supuesto Gmail. Pero parece que algo aún mejor estará disponible pronto, Google Wave. La idea es que mucha gente puede colaborar al mismo tiempo usando Google Wave como la plataforma de enlace. Abajo está el video con la demo.

Despite the fact that I do not use Chrome as my predetermined browser, I use many Google applications (I prefer Mozilla). For example, I look for addresses and calculate distances in Google Maps, I read all the blogs I follow in Google Reader, I write my blog in Blogspot, I keep track of the statistics of my blogs in Google Analytics, and the most amazing of the applications Google has created so far and I use is Gmail of course! I can read all my mails there from all my different accounts. But now something even more amazing seems to be coming, Google Wave. It is a tool for collaboration. Suppose you have to write a final project for one of your courses, and since it is the end of the semester you have a lot of other things to do. Google Wave will let your team post their ideas in a single document, you can track who said what and you can see the changes of the document through a sort of time line. One of the most astonishing features is that more than one person can be modifying a document and everyone can see the modifications being done at the same time. It can be interacted with twitter and facebook and all the Google applications. I bet that with Google Wave that final project can be done in one night if all the members of the team get online, without having to meet in a certain place.

It is not available yet though. This is the video of the demo.