The scatterplot above shows the diameter x, in inches, and the age y, in years, of more than 40 trees in a certain park. Which of the following best describes the trend line of the scatterplot?

A) 2x+20

B) 5x+20

C) 10x+20

D) y=4x

E) y=12xI got this one right, but it was really just a lucky guess. Scatterplots make no sense to me.

For this one, I think it’s more useful to think about the slope than it is to try to figure out the *y*-intercept. And to think about the slope, you need to pay attention to the scales on the *x*– and *y*– axes. I think a line that does a *pretty* decent job of approximating the trend can be drawn from the farthest left and farthest right points: about (1, 30) and (27, 150). What is the slope of that line?

That rounds to about 5, which makes choice B look pretty good.