Discussion - Professor Abadi is evaluating the relationship

Discussion

Professor Abadi is evaluating the relationship between food intake and ability to quickly complete a timed task. He provides a buffet lunch to all study participants. They can eat as much or as little as they want. Their plates of food are photographed and weighed before and after eating to estimate caloric intake. Thirty minutes later, they are given a timed attention task in which they must complete a puzzle on a computer screen as quickly as they can.
The following graph shows the results of Professor Abadi's study:

Answer the following questions:

1. What kind of correlation (positive, negative or none) do you see reflected in the graph? Why did you answer the way you did?

2. What are 3 possible causal interpretations for this graph, if you think a correlation is occuring?  Be specific to the variables shown.

3. Can we definitively determine which of these interpretations is the correct one? Why or why not?