AP Statistics Practice Test

The statement that correlation values range from -1 to 1 is true. This range indicates the strength and direction of a linear relationship between two quantitative variables. A correlation of -1 signifies a perfect negative linear relationship, where as one variable increases, the other decreases in a perfectly linear fashion. A correlation of 1 indicates a perfect positive linear relationship, where both variables increase together in a linear manner. A correlation of 0 suggests no linear relationship between the variables. The other statements do not accurately describe correlation: while correlation can suggest a relationship, it does not imply causation, illustrating that correlation alone cannot prove that one variable causes a change in another. Higher correlation does indicate a stronger linear relationship but does not mean the data points are perfectly linear unless the correlation is exactly 1 or -1. Lastly, correlation is not affected by the mean values of the variables; it measures how closely data points conform to a linear model irrespective of their average values.