The correlation coefficient is a statistical measure that quantifies the strength and direction of the relationship between two variables. It is represented by the symbol ‘r’ and ranges from -1 to 1, with a value of 0 indicating no correlation and values closer to -1 or 1 indicating a strong negative or positive correlation, respectively. In simpler terms, the correlation coefficient helps us understand how closely related two variables are, and whether they tend to increase or decrease together. It is a valuable tool in analyzing data and making predictions in various fields such as economics, psychology, and science.