condition mean min max ZT0-3 2.4457166666666668 1.71207 2.830155 ZT4-7 2.223395 2.223395 2.223395 ZT8-11 2.9080199999999996 2.9080199999999996 2.9080199999999996 ZT12-15 2.74880325 2.5026465 2.99496 ZT16-19 4.1478850000000005 4.1478850000000005 4.1478850000000005 ZT20-23 1.8190369999999998 1.8190369999999998 1.8190369999999998