Correlation and association

Correlation analysis explores the association between two or more variables and makes inferences about the strength of the relationship.

• Scatter plot
  A scatter plot shows the association between two variables. A scatter plot matrix shows all pairwise scatter plots for many variables.
• Covariance
  Covariance is a measure of how much two variables change together. A covariance matrix measures the covariance between many pairs of variables.
• Correlation coefficient
  A correlation coefficient measures the association between two variables. A correlation matrix measures the correlation between many pairs of variables.
• Inferences about association
  Inferences about the strength of association between variables are made using a random bivariate sample of data drawn from the population of interest.