condition mean min max ZT0-3 74.55385 68.707 80.4007 ZT4-7 19.34545 19.34545 19.34545 ZT8-11 10.16845 10.16845 10.16845 ZT12-15 0 0 0 ZT16-19 24.493450000000003 24.493450000000003 24.493450000000003 ZT20-23 40.38675 40.38675 40.38675