Interpret an r value of -0.82.?

Answer 1

If x and y have a strong negative linear correlation, r is close to -1. An r value of exactly -1 indicates a perfect negative fit. Negative values indicate a relationship between x and y such that as values for x increase, values for y decrease.

So I would say that x and y have a strong negative linear correlation.

Taking r^2 = 0.6724 = 67.24% of the total variation in y can be explained by the linear relationship between x and y. The other 32.76% remains unexplained.

Answer 2

Here is a graph of .8 which is close to what you have: http://upload.wikimedia.org/wikipedia/en/c/c4/Corr-example.png
The way to read this is the diagonal is all r=1 and the rest of the relations are in the opposite positions. The .8 is in the first column... and the third box down. If would look like this but negative (downward sloping).



So your point are gonna follow some linear downward slope, and we can fit a line to this and have a fairly accurate relationship (not -1, because that would be if they were all in an exact downward sloping line).

Here is a general graph that explains the relationships:
http://hosting.soonet.ca/eliris/remotesensing/LectureImages/correlation.gif

Just remember that just because it has a correlation of r=0 doesn't mean there isn't some correlation: http://www.uwsp.edu/psych/stat/7/i30.gif ...

These points are obviously related and we can come up with a model to predict the next one.

Answer 3

|r| > 0.5 implies a fit of sorts. r = -0.82 is pretty good, but there may be a better fit if another function is used.