Correlation and Regression

Concept:The Pearson correlation coefficient $r$ measures the strength and direction of a linear relationship between two variables.Explanation:If $r = 0$, it indicates no linear correlation between $x$ and $y$.This means changes in $x$ are not linearly associated with changes in $y$.Option A (perfect correlation) requires $r = \pm 1$.Option C (positive correlation) requires $r > 0$.Option D is incorrect because $r = 0$ is a valid value.Thus, the correct choice is B.Answer:$x$ and $y$ are not correlated.