Funding for this research was provided by:
National Natural Science Foundation of China (71472156)
Text and Data Mining valid from 2019-01-23
First Online: 23 January 2019
Compliance with Ethical Standards
: All authors declare no conflict of interest.
: The study was not preregistered. Data cannot be made publicly available because this would violate the confidentiality agreement in the informed consent. The dataset contains sensitive personal information (i.e., full name, parents information and home address), which was not allowed to be made publicly to protect the privacy and the security of the students.