Which is most likely the correlation coefficient for the set of data shown?
–0.872
–0.191
0.191
0.872

The correct answer is:

0.872.

Explanation:

The correlation coefficient of a regression line is a measure of how closely the line fits our data.  Negative correlation coefficients represent decreasing lines; positive correlation coefficients represent increasing lines.

The closer a correlation coefficient is to +1 or -1, the better the fit; a perfect positive fit is r=1 and a perfect negative fit is r=-1.

We can see in the graph that the line is very close to our data, so it is a pretty good fit.

The line is increasing; this means we want a correlation coefficient that is close to 1.

The best choice is 0.872.

Just divide the x axis (the top) by 2 or multiply the y axis (the bottom) by 2