Section 4.1 Summary

1. For two quantitative variables, scatterplots summarize the relationship by plotting all the points.
2. The correlation coefficient is a measure of the strength of linear association between two numeric variables. Values of close to 1 indicate that the variables are positively correlated. Values of close to −1 indicate that the variables are negatively correlated. Values of close to 0 indicate that the variables are not linearly correlated.