What does a scatter plot look like?

From LiteracyTentWiki

This is an invitation to enter a short discussion of looking at a typical scatter plot question ...

First some definitions....

line of best fit 
A straight line drawn through or near to as many data points as possible on a scatterplot.
scatter plot 
Two sets of data plotted as ordered pairs in a graph or chart, e.g. created in Excel.


(Source of definitions: http://www.doe.mass.edu/frameworks/math/2000/append3.html#best_fit)

Now try this problem...

http://www.doe.mass.edu/frameworks/math/2000/all.asp?id=dat09_i


If you got the right answer, please explain your reasoning below by editting this page and posting your thinking here. Let's start a learning discussion here...I'll start.


From ABEstimator (Posted 10/07/05): I think the first skill I might be using is, in my "mind's eye," I found the "line of best fit" for each of the graphs. Note, if you can't do it by visualizing, you could take a straight edge -- a piece of dry spaghetti would do -- and try to find the "line of best fit." Then, once I found those lines, I drew some inferences from them, using my knowledge of slope of a straight line.