condition mean min max ZT0-3 1.8658486666666667 0.788993 3.918775 ZT4-7 1.073542 1.073542 1.073542 ZT8-11 1.25675 1.25675 1.25675 ZT12-15 3.1053175000000004 1.760435 4.450200000000001 ZT16-19 1.463165 1.463165 1.463165 ZT20-23 1.2325 1.2325 1.2325