Dataset supporting the paper: Z. Huang, M. England, J.H. Davenport and L.C. Paulson Using Machine Learning to decide when to Precondition Cylindrical Algebraic Decomposition with Groebner Bases. Proceedings of the 18th International Symposium on Symbolic and Numeric Algorithms for Scientific Computing (SYNASC '16), pp. 45--52. IEEE, 2016. Digital Object Identifier: http://dx.doi.org/10.1109/SYNASC.2016.020