A.3.3—Linear relationships

For y = mx + c, m is the change in y per unit change in x and c is the y-intercept. Units must be carried into both quantities.

Choose two well-separated points on the fitted line, calculate rise/run and use the intercept only within the model’s measured domain.

If oxygen production rises 4 units for each 2 °C, the slope is 2 units °C⁻¹; it does not mean temperature alone caused the change.

A straight trend over one range does not guarantee linearity outside it or prove the intercept is biologically attainable.