condition mean min max ZT0-3 6.17957127325 5.299219561499999 7.059922985 ZT4-7 4.5198640569999995 4.1134449349999995 4.926283179 ZT8-11 6.3815267342499995 5.535468229999999 7.2275852385 ZT12-15 5.39505623625 5.323977872 5.4661346005 ZT16-19 5.0430115145 4.39420176 5.691821269 ZT20-23 6.7675840505 6.710758699 6.824409402000001