Writing a model to represent data set ?

[Rizzamabob]

What exactly does this mean, i have a set of data and it asks me to write a model for it, and to define all non-arithmetic peices in my model. The data shows no real symmetry or anything. What type of "model" should i be writing ?
Here is the data.

 

[EnumaElish]

Homework, right?

 

[Hurkyl]

The data shows no real symmetry or anything.

The data shows lots of stuff. For example, I find it quite striking that the data seems to be organized into four bands, and the density on the left is far greater than the density on the right.