The left plot shows epsilon in mean of theta percent against theta over L with scattered points and a fitted line labelled y equals 84.07 x plus 0.55. Values increase linearly from about 3 to about 22 percent. The right plot shows sigma of theta percent versus theta over L with a fitted line labelled y equals 2.13 x plus 0.38. Sigma increases from about 0.42 to about 0.92, showing a clear linear relationship.
Empirical relationship derived using linear regression analysis for (a) in mean of against and (b) in mean of against