Econometrics is the branch of economics that draws heavily on statistics for testing and analyzing economic relationships. Within econometrics, there are theoretical econometricians who analyze statistical properties of estimators of models. Several recipients of the Nobel Prize in Economic Sciences received the award as a result of their lifetime contribution to this branch of economics. To appreciate the importance of econometrics to the discipline of economics, when the first Nobel Prize in Economic Sciences was awarded in 1969, the co-recipients were two econometricians, Jan Tinbergen and Ragnar Frisch (the latter credited for first using the term econometrics in the sense that it is known today). The co-recipient of the 2013 Nobel Prize was Lars Peter Hansen who had made major contributions to the field of econometrics. Further specialization within econometrics, and the area that directly relates to this book, is financial econometrics. As Jianqing Fan writes, the field of financial econometrics