Christopher R. Barbour’s address was incorrect at the time of online publication of this article. It has been updated as follows:
C.R. Barbour, Statistical Consulting and Research Services, Montana State University, PO Box 172400, Bozeman, Montana, 59717-2400, United States of America.
In addition, funding information was not included in the acknowledgement in the originally published article. It has now been added as follows:
Research reported in this publication was supported by the National Institute of General Medical Sciences of the National Institutes of Health under award number P20GM103474. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
The address has been corrected and funding information added in the online version of this article.