In statistics, two quantities are said to be correlated if greater values of one tend to be associated with greater values of the other (positively correlated), or if greater values of one tend to be associated with lesser values of the other (negatively correlated). The correlation (or, more formally, correlation coefficient) between two variables is a number measuring the strength and usually the direction of this relationship.
In statistics, two quantities are said to be correlated if greater values of one tend to be associated with greater values of the other (positively correlated), or if greater values of one tend to be associated with lesser values of the other (negatively correlated). The correlation (or, more formally, correlation coefficient) between two variables is a number measuring the strength and usually the direction of this relationship. In the case of interval or ratio variables, non-zero correlation is often apparent in a scatterplot of the data points: positive correlation is reflected in an overall increasing trend in the points (when viewed from left to right on the graph), whereas negative correlation appears as an overall decreasing trend.