condition mean min max ZT0-3 2.2447848333333336 0.6479745 3.28505 ZT4-7 0.7575135 0.7575135 0.7575135 ZT8-11 1.151365 1.151365 1.151365 ZT12-15 1.8047425000000001 1.329835 2.27965 ZT16-19 2.98262 2.98262 2.98262 ZT20-23 3.6502 3.6502 3.6502