Statistical comments on "no seasonal variation in physical activity of Han Chinese living in Beijing"

[...]they measured their variables in one group of 40 adults every two months across a complete year. [...]there were not independent groups in this study and they investigated one group at different time points. Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.