condition mean min max ZT0-3 1.95208 1.3666800000000001 2.992225 ZT4-7 1.99709 1.99709 1.99709 ZT8-11 1.5082200000000001 1.5082200000000001 1.5082200000000001 ZT12-15 1.9186135000000002 0.9536469999999999 2.8835800000000003 ZT16-19 0.944143 0.944143 0.944143 ZT20-23 1.460665 1.460665 1.460665