Identify all true statements about the correlation coefficient, r. The value of r ranges from negative one to positive one. When the data points in a scatter plot fall closely around a straight line that is either increasing or decreasing, t correlation between the two variables is strong. The sign of r describes the direction of the association between two variables. If two variables are negatively correlated, when one variable increases, the other variable also increases. A correlation coefficient of zero means that no relationship exists between the two variables. The correlation coefficient is not affected by outliers.