Help with analysing graph

Hey spacecadeta and welcome to the forums.

You need to show what you have done and tried, what you are thinking (i.e. your thought process) and specifically where you are having trouble.

If you need to graph something, a good package is R:

http://www.r-project.org/

If you have been recommended to use something else from your teacher (since this is clearly a homework/assignment problem) then use that.

We do the above because you don't learn if you just get all the answers: if your question was more specific, then things might be different but they aren't.

 

Well in general, finding fitting models is a pretty ugly thing.

What kinds of things can you think of that the model "looks like"? Sine or cosine curve? Exponential? Square or Cube?

If you show us your ideas (and the graph you generated as an attachment), you might get more specific suggestions.

 

Even a series of connected straight line graphs could do as a model here. The idea is to pick a model and discuss where it fits the data and doesn't. Even if the model isn't a good fit, you will get high marks if your discussion of the model strengths and faults is good. For instance, three or four straight lines connected together could be caused by a trend of increasing yields that decreased as a result of an unknown event and such cycle repeats.