About the Authors

Hao Chen

Affiliation Department of Statistics, Stanford University, Stanford, California, United States of America

Haipeng Xing

Affiliation Department of Applied Mathematics and Statistics, SUNY at Stony Brook, Stony Brook, New York, United States of America

Nancy R. Zhang

nzhang@stanford.edu

Affiliation Department of Statistics, Stanford University, Stanford, California, United States of America

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Analyzed the data: HC NRZ. Wrote the paper: HC HX NRZ. Designed methodology: NRZ HC HX.