condition mean min max ZT0-3 3.7945290697500003 1.5113853095 6.07767283 ZT4-7 3.34497539075 1.9758154115000002 4.71413537 ZT8-11 5.86500367225 5.4227421085000005 6.307265236 ZT12-15 4.1165477815 3.1283811475 5.1047144155 ZT16-19 9.11386178425 4.7563537325 13.471369836000001 ZT20-23 17.17304089 12.642281505 21.703800275