When analyzing many variables, scatter plots and correlation coefficients can quickly
uncover patterns and reduce a large amount of data to a subset of interesting relationships.
Correlation describes the strength of relationship between two variables. A
correlation coefficient ranges from -1 to +1. +1 indicates a perfect positive linear
relationship, and -1 indicates a perfect negative linear relationship. Zero indicates
the variables are uncorrelated and there is no linear relationship. Normally the
correlation coefficient lies somewhere between these values.
The scatter plot matrix shows plots for all of the pairs of variables, and each
plot shows the relationship between a pair of variables. The red ellipse contains
the middle 75% of the neighborhoods and indicates whether the two variables are
positively, negatively, or not correlated.
The correlation matrix shows the correlation coefficient for each pair of
variables. Positively correlated variables are blue and negatively correlated
variables are red, with the intensity dependent on the magnitude of the