Everything, but do not treat R2 as the measure of linearity... This is another reminder about the correct understanding of calibration dependence .
- F. Raposo, "Evaluation of analytical calibration based on least-squares linear regression for instrumental techniques: A tutorial review", TrAC Trends in Analytical Chemistry, vol. 77, pp. 167-185, 2016. http://dx.doi.org/10.1016/j.trac.2015.12.006