What italicized letter represents the correlation coefficient? \( t \) \( z \) \( r \) \( s \)

The italicized letter that represents the correlation coefficient is \( r \). This statistical term measures the strength and direction of a linear relationship between two variables. Ranging from -1 to 1, a value of \( r = 1 \) indicates a perfect positive correlation, while \( r = -1 \) signifies a perfect negative correlation. An \( r \) value of 0 means there's no linear relationship at all—how fun is that? In practice, the correlation coefficient is widely used in fields like psychology, finance, and biology. For instance, researchers might use it to analyze the relationship between study hours and exam scores or explore the link between income levels and health outcomes. Understanding \( r \) can help identify trends and inform decisions based on data, adding a scientific flair to everyday choices!