8 CHAPTER 6: CORRELATION Key Terms Positive relationship - Occurs in so far as pairs of observations tend to occupy similar relative positions in their respective distribution. Negative relationship - Occurs in so far as pairs of observations tend to occupy dissimilar relative positions in their respective distribution. Scatterplot m a graph containing a cluster of dots that represents all pairs of observations. Person correlation coefficient -- A number between 1 and +1 that describes the linear relationship between pairs of quantitative variables. Linear relationship --- A relationship that can be described with a straight line. Curvilinear relationship - A relationship that can be described with a curved line. Correlation coefcient (r) m Anumber between 1 and +1 that describes the relationship between pairs of variables Correlation matrix M Table showing correlations for all possible pairs of variables. Text Review In previous chapters, we have examined individual data sets representing collections of records or observations of some characteristic that varied among individuals (e. g., height, weight, and IQ scores, or popping time for kernels of corn and average burning time for light bulbs). In statistics, sinc