Slope of a Line

The trend actually depends on how the variable y behaves as the variable x increases.

- For increasing line, the variable y increases as the x increases.

- For decreasing line, the variable y decreases as the variable x increases.

The variable x is often called the independent variable, and the variable y is the dependent variable.

It should be clear from the plot above what it means for the slope of a line to be positive. As one moves to the right along the x-axis, the values of the y-coordinate of points on the line are also increasing.

When taken as trend lines, it is sometimes said that in these cases, "the y variable is positively correlated with the x variable."