condition mean min max ZT0-3 15.5485336225 14.88107957 16.215987675 ZT4-7 14.756690026666668 13.10458854 16.408791513333334 ZT8-11 15.388834748333334 14.38011348 16.397556016666666 ZT12-15 9.886462227500001 8.501239019 11.271685436 ZT16-19 9.137828012 8.734337034 9.54131899 ZT20-23 6.941519172 6.0930495339999995 7.7899888100000005