Hi, I am working on a biology lab regarding the tree algea, pleurococcus and how its density on trees is affected by direction (N,S,E,W) and light received from each direction. Here is a screenshot of the data I have access to: http://tinypic.com/r/jugxa1/6 My question is: what would you guys think would be the best way to compare the data? I was thinking. Graph the average light received from each direction and graph the average density received from each direction. While that seems to show a bit of a relationship (e.g. on average south gets the second highest light and highest pleur. density). But I was wondering if you guys think there would be a better way to do this? And would a T-Test be a good thing to perform, if so, which two sets of data would I be testing? Thanks a lot.