In Exercises $39-44,$ plot the points and determine whether the data have positive, negative, or no linear correlation (see figures below). Then use a graphing utility to find the value of $r$ and confirm your result. The number $r$ is called the correlation confficient. It is a measure of how well the model fits the data. Correlation coefficients vary between $-1$ and $1,$ and the closer $|r|$ is to $1,$ the better the model.
(GRAPH NOT COPY)
Positive correlation Negative correlation No correlation
$$
(1,4),(2,6),(3,8),(4,11),(5,13),(6,15)
$$