The steeper the curve, the greater the antioxidant activity. As the graph shows, UVR has reduced the antioxidant activity of the trans-resveratrol solution. Also shown are the trend lines (logarithmic regression), their equations, and the “R squared,” a statistical measure of how well the trend line matches the actual data. A perfect fit is R2 = 1. In both cases the trend lines are very close fits to the data.