condition mean min max ZT0-3 14.452552 14.452552 14.452552 ZT4-7 12.798032 12.798032 12.798032 ZT8-11 12.6258135 12.6258135 12.6258135 ZT12-15 12.408267500000001 12.408267500000001 12.408267500000001 ZT16-19 13.7702165 13.7702165 13.7702165 ZT20-23 12.3599985 12.3599985 12.3599985